A distributed call pickup group system comprises a call manager having an extension module. The extension module further comprises a group pickup module, a group pickup call stack, a backup group pickup module and a monitoring group pickup module. The extension module controls and manages the functionality associated with the group pickup feature. The group pick module advantageously allows any extension regardless of its location in the system or the switch to which it is connected to be included within a pickup group. The backup group pickup module provides fault tolerance for the pickup functionality such that if a particular switch and its associated group pickup module fail, a backup group pickup module is identified and made operational. The present invention also includes a variety of methods including a method for creating a group pickup list, a method for performing through pickup and a method for backing up group picked up.

1. Field of the Invention
The present invention relates telephony systems such as that using Voice over Internet Protocol (VoIP). In particular, the present invention relates to a group pickup feature for telephony systems.
2. Description of the Background Art
The prior art includes a variety of distributed telephony systems. Traditional switched network systems have given way to new telephony systems that use VoIP. These VoIP systems offer the same functionality as more traditional switched system such as the ability to transfer calls, put calls on hold, automated attendant functions, hunt groups, etc. These systems also offer additional functionality, for example, call group pickup. Call pickup group is a traditional PBX and key system feature that is used in group work environments. With call group pickup, calls to a pre-designated group of phones can be answered by issuing a pickup command on group pickup number. Thus, the call group pickup feature allows users with the proper class of service to pickup a call on any telephone in a pickup group from any other telephone.
However, existing implementations of the call pickup group feature have a number of shortcomings. First, if the switch or server becomes non-operational for any reason, the call pickup group features not available. Second, prior art systems typically include restrictions as to until which phones or endpoints can be included within a call pickup group. For example, the endpoints are often limited to those endpoints directly connected to the switch or at a particular location. Third, typically the prior art only allows an extension to be assigned to a single pickup group. Fourth, existing systems that provide a call pickup group feature are very difficult to configure. In some cases, it can only be done by a system administrator. Were it can be done by the user, it is very difficult to step up and add or remove users from pickup lists and manage the lists. This severely limits the use and application of pickup groups.

Distributed call pickup group for VoIP system


Overlapped wireless LAN cells in a medium have an equal chance at establishing a session on the medium. A first member station in the first cell transmits a timing packet containing a timestamp value, which is received at a second member station in the second cell. This synchronizes member stations in the first and second cells to interrupt transmissions at a global channel release instant corresponding to the timestamp value. The member stations in the first and second cells then have the opportunity to contend for access to the medium following the global channel release instant, using a slotted CSMA/CA access method. Each of the member stations in the first and second cells has a superframe clock that is synchronized based on the timestamp value, thereby establishing a periodic global channel release instant during each of a plurality of periodic superframes. The member stations can then periodically interrupt transmissions at the periodic global channel release instant to contend for the medium. The periodic global channel release instant occurs at intervals that are sufficiently close to meet delay and jitter restrictions for time-critical voice and video applications.

A single-cell wireless LAN using the IEEE 802.11 Wireless LAN Standard is a Basic Service Set (BSS) network. When all of the stations in the BSS are mobile stations and there is no connection to a wired network, it is an independent BSS (IBSS). An IBSS has an optional backbone network and consists of at least two wireless stations. A multiple-cell wireless LAN using the IEEE 802.11 Wireless LAN Standard is an Extended Service Set (ESS) network. An ESS satisfies the needs of large coverage networks of arbitrary size and complexity.
The IEEE 802.11 Wireless LAN Standard is published in three parts as IEEE 802.11-1999, IEEE 802.11a-1999, and IEEE 802.11b-1999, which are available from the IEEE, Inc. web site http://grouper.ieee.org/groups/802/11. The IEEE 802.11 Wireless LAN Standard defines at least two different physical (PHY) specifications and one common medium access control (MAC) specification. The IEEE 802.11(a) Standard is designed to operate in unlicensed portions of the radio spectrum, usually either in the 2.4 GHz Industrial, Scientific, and Medical (ISM) band or the 5 GHz Unlicensed-National Information Infrastructure (U-NII) band. It uses orthogonal frequency division multiplexing (OFDM) to deliver up to 54 Mbps data rates. The IEEE 802.11(b) Standard is designed for the 2.4 GHz ISM band and uses direct sequence spread spectrum (DSSS) to deliver up to 11 Mbps data rates.
Other wireless LAN standards include: Open Air (which was the first wireless LAN standard), HomeRF (designed specifically for the home networking market), and HiperLAN/2 (the European counterpart to the "American" 802.11a standard). Bluetooth is a personal area network (PAN) standard. It is aimed at the market of low-power, short-range, wireless connections used for remote control, cordless voice telephone communications, and close-proximity synchronization communications for wireless PDAs/hand-held PCs and mobile phones.
The IEEE 802.11 Wireless LAN Standard describes two major components, the mobile station and the fixed access point (AP). IEEE 802.11 networks can also have an independent configuration where the mobile stations communicate directly with one another, without support from a fixed access point. The medium access control (MAC) protocol regulates access to the RF physical link. The MAC provides a basic access mechanism with clear channel assessment, channel synchronization, and collision avoidance using the Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) access method. The MAC provides link setup, data fragmentation, authentication, encryption, and power management.
Synchronization is the process of the stations in an IEEE 802.11 wireless LAN cell getting in step with each other, so that reliable communication is possible. The MAC provides the synchronization mechanism to allow support of physical layers that make use of frequency hopping or other time-based mechanisms where the parameters of the physical layer change with time. The process involves sending a beacon packet to announce the presence of a wireless LAN cell and inquiring to find a wireless LAN cell. Once a wireless LAN cell is found, a station joins the wireless LAN cell. This process is entirely distributed in wireless LAN cells and relies on a common timebase provided by a timer synchronization function (TSF). The TSF maintains a 64-bit timer running at 1 MHz and updated by information from other stations. When a station begins operation, it resets the timer to zero. The timer may be updated by information received in a beacon packet.
In an independent BSS (IBSS) wireless LAN cell, there is no access point (AP) to act as the central time source for the wireless LAN cell. In a wireless LAN cell, the timer synchronization mechanism is completely distributed among the mobile stations of the wireless LAN cell. Since there is no AP, the mobile station that starts the wireless LAN cell will begin by resetting its TSF timer to zero and transmitting a beacon packet, choosing a beacon period. This establishes the basic beaconing process for this wireless LAN cell. After the wireless LAN cell has been established, each station in the wireless LAN cell will attempt to send a beacon after the target beacon transmission time (TBTT) arrives. To minimize actual collisions of the transmitted beacon frames on the medium, each station in the wireless LAN cell will choose a random delay value, which it will allow to expire before it attempts its beacon transmission.
In order for a mobile station to communicate with other mobile stations in a wireless LAN cell, it must first find the stations. The process of finding another station is by inquiry. The inquiring may be either passive or active. Passive inquiry involves only listening for IEEE 802.11 traffic. Active inquiry requires the inquiring station to transmit and invoke responses from IEEE 802.11 stations.
Active inquiry allows an IEEE 802.11 mobile station to find a wireless LAN cell while minimizing the time spent inquiring. The station does this by actively transmitting queries that invoke responses from stations in a wireless LAN cell. In an active inquiry, the mobile station will move to a channel and transmit a probe request frame. If there is a wireless LAN cell on the channel that matches the service set identity (SSID) in the probe request frame, the responding station in that wireless LAN cell will respond by sending a probe response frame to the inquiring station. This probe response includes the information necessary for the inquiring station to extract a description of the wireless LAN cell. The inquiring station will also process any other received probe response and beacon frames. Once the inquiring station has processed any responses, or has decided there will be no responses, it may change to another channel and repeat the process. At the conclusion of the inquiry, the station has accumulated information about the wireless LAN cells in its vicinity.
Joining a wireless LAN cell requires that all of the mobile station's MAC and physical parameters be synchronized with the desired wireless LAN cell. To do this, the station must update its timer with the value of the timer from the wireless LAN cell description, modified by adding the time elapsed since the description was acquired. This will synchronize the timer to the wireless LAN cell. Once this process is complete, the mobile station has joined the wireless LAN cell and is ready to begin communicating with the stations in the wireless LAN cell.
Each wireless station and access point in an IEEE 802.11 wireless LAN implements the MAC layer service, which provides the capability for wireless stations to exchange MAC frames. The MAC frame is a packet that transmits management, control, or data between wireless stations and access points. After a station forms the applicable MAC frame, the frame's bits are passed to the Physical Layer for transmission.
Before transmitting a frame, the MAC layer must first gain access to the network. Three interframe space (IFS) intervals defer an IEEE 802.11 station's access to the medium and provide various levels of priority. Each interval defines the duration between the end of the last symbol of the previous frame to the beginning of the first symbol of the next frame. The Short Interframe Space (SIFS) provides the highest priority level by allowing some frames to access the medium before others, such as an Acknowledgement (ACK) frame, a Clear-to-Send (CTS) frame, or a subsequent fragment burst of a previous data frame. These frames require expedited access to the network to minimize frame retransmissions.
The Priority Interframe Space (PIFS) is used for high priority access to the medium during the contention-free period. A point coordinator in the access point connected to the backbone network controls the priority-based Point Coordination Function (PCF) to dictate which stations in a cell can gain access to the medium. The point coordinator in the access point sends a contention-free poll frame to a station, granting the station permission to transmit a single frame to any destination. All other stations in the cell can only transmit during a contention-free period if the point coordinator grants them access to the medium. The end of the contention-free period is signaled by the contention-free end frame sent by the point coordinator, which occurs when time expires or when the point coordinator has no further frames to transmit and no stations to poll.
The distributed coordination function (DCF) Interframe Space (DIFS) is used for transmitting low priority data frames during the contention-based period. The DIFS spacing delays the transmission of lower priority frames to occur later than the priority-based transmission frames. An Extended Interframe Space (EIFS) goes beyond the time of a DIFS interval as a waiting period when a bad reception occurs. The EIFS interval provides enough time for the receiving station to send an acknowledgment (ACK) frame.
During the contention-based period, the distributed coordination function (DCF) uses the Carrier-Sense Multiple Access With Collision Avoidance (CSMA/CA) contention-based protocol, which is similar to IEEE 802.3 Ethernet. The CSMA/CA protocol minimizes the chance of collisions between stations sharing the medium by waiting a random backoff interval if the station's sensing mechanism indicates a busy medium. The period of time immediately following traffic on the medium is when the highest probability of collisions occurs, especially where there is high utilization. Once the medium is idle, CSMA/CA protocol causes each station to delay its transmission by a random backoff time, thereby minimizing the chance it will collide with those from other stations.
In the IEEE 802.11 Standard, the channel is shared by a centralized access protocol, the Point Coordination Function (PCF), which provides contention-free transfer based on a polling scheme controlled by the access point (AP) of a basic service set (BSS). The centralized access protocol gains control of the channel and maintains control for the entire contention-free period by waiting the shorter Priority Interframe Space (PIFS) interval between transmissions than the stations using the Distributed Coordination Function (DCF) access procedure. Following the end of the contention-free period, the DCF access procedure begins, with each station contending for access using the CSMA/CA method.
The 802.11 MAC Layer provides both contention and contention-free access to the shared wireless medium. The MAC Layer uses various MAC frame types to implement its functions of MAC management, control, and data transmission. Each station and access point on an 802.11 wireless LAN implements the MAC Layer service, which enables stations to exchange packets. The results of sensing the channel to determine whether the medium is busy or idle are sent to the MAC coordination function of the station. The MAC coordination also carries out a virtual carrier sense protocol based on reservation information found in the Duration Field of all frames. This information announces to all other stations the sending station's impending use of the medium. The MAC coordination monitors the Duration Field in all MAC frames and places this information in the station's Network Allocation Vector (NAV) if the value is greater than the current NAV value. The NAV operates similarly to a timer, starting with a value equal to the Duration Field of the last frame transmission sensed on the medium and counting down to zero. After the NAV reaches zero, the station can transmit if its physical sensing of the channel indicates a clear channel.
At the beginning of a contention-free period, the access point senses the medium; and if it is idle, it sends a beacon packet to all stations. The beacon packet contains the length of the contention-free interval. The MAC coordination in each member station places the length of the contention-free interval in the station's Network Allocation Vector (NAV), which prevents the station from taking control of the medium until the end of the contention-free period. During the contention-free period, the access point can send a polling message to a member station, enabling it to send a data packet to any other station in the BSS wireless cell.
Quality of service (QoS) is a measure of service quality provided to a customer. The primary measures of QoS are message loss, message delay, and network availability. Voice and video applications have the most rigorous delay and loss requirements. Interactive data applications such as Web browsing have less restrained delay and loss requirements, but they are sensitive to errors. Non-real-time applications such as file transfer, email, and data backup operate acceptably across a wide range of loss rates and delay. Some applications require a minimum amount of capacity to operate at all—for example, voice and video. Many network providers guarantee specific QoS and capacity levels through the use of Service-Level Agreements (SLAs). An SLA is a contract between an enterprise user and a network provider that specifies the capacity to be provided between points in the network that must be delivered with a specified QoS. If the network provider fails to meet the terms of the SLA, then the user may be entitled a refund. The SLA is typically offered by network providers for private line, frame relay, ATM, or Internet networks employed by enterprises.
The transmission of time-sensitive and data application traffic over a packet network imposes requirements on the delay or delay jitter, and the error rates realized; these parameters are referred to generically as the QoS (Quality of Service) parameters. Prioritized packet scheduling, preferential packet dropping, and bandwidth allocation are among the techniques available at the various nodes of the network, including access points, that enable packets from different applications to be treated differently, helping achieve the different quality of service objectives. The above-cited, copending U.S. patent application, entitled "Tiered Contention Multiple Access (TCMA): A Method for Priority-Based Shared Channel Access," describes the Tiered Contention Multiple Access (TCMA) distributed medium access protocol that schedules transmission of different types of traffic based on their QoS service quality specifications.
For multiple-cell wireless LANs, the limited availability of channels implies that the channels must be re-used, much like in cellular communication networks. But unlike in cellular networks, the number of channels available in wireless LANs is not adequate to ensure both contiguous coverage (which is essential for roaming) and interference-free connections at the same time. As a result, cells assigned the same channel may experience co-channel interference in the area of overlapping coverage or near a cell's periphery. The problem of overlapping cell coverage is acute when wireless LANs are installed without any awareness of what other wireless LANs are operating nearby. Consequently, multiple-cell wireless LANs must rely on a medium access control (MAC) protocol to allocate channel time among stations in order to avoid co-channel interference between cells, just as it avoids contention among stations within the same cell.
Special MAC protocols are provided for wireless LANs because transmission is flawed by higher bit error rates, different losses are experienced on a wireless channel depending on the path on which the signal travels, and a radio node cannot listen while transmitting. Additive noise, path loss and multipath result in more retransmissions and necessitate acknowledgements, as successful transmission cannot be taken for granted. The different losses experienced along different paths cause different nodes to receive transmissions at different strengths, giving rise to the phenomenon of hidden terminals, as is known in the art. These are terminals that cannot hear or be heard by a source but are capable of causing interference to the destination of a transmission. The message exchange mechanism known in the art as Request-to-Send/Clear-to-Send (RTS/CTS) alleviates the hidden terminal problem. RTS/CTS also provides a reservation mechanism that can save bandwidth in wireless LANs. The inability to detect a collision as quickly as it can be detected on cable with carrier-sense multiple access with collision detection (CSMA/CD) causes more channel time to be wasted in a collision while waiting for the entire frame to transmit before the collision is detected. Hence, carrier sensing is combined with the RTS/CTS mechanism to give carrier-sense multiple access with collision avoidance (CSMA/CA).
All channel reservations, generated either with an RTS/CTS exchange or for a contention-free period (CFP), are made with the aid of the Network Allocation Vector (NAV), which is a timer maintained by all stations. The NAV is set at the value of the duration field broadcast when the reservation is announced, either by the RTS or CTS frames, or with the PCF beacon transmitted by the AP to initiate the CFP. All stations in a cell defer access until the NAV expires. The NAV thus provides a virtual carrier-sense mechanism.
Receiving signals at different strengths, depending on their origin, gives rise to capture effects. A known capture effect, the "near-far capture," results from stronger signals being received successfully while other stations transmit at the same time. Near-far capture leads to inequities, as throughput is greater for nearby stations while distant stations are starved. In infrastructure wireless LANs, where all communications occur through the AP, the inequity can be remedied by applying power control at the station (i.e., on the uplink). By equalizing the signal strength received at the AP, all transmissions have equal probabilities of success.
A special IEEE 802.11 study group is working on enhancements to the MAC protocols that achieve acceptable QoS for Wireless LANs. Proposals for a QoS enhanced DCF (EDCF) mechanism and a QoS enhanced PCF (EPCF) mechanism are under review.
The proposed EDCF mechanism employs the Tiered Contention Multiple Access (TCMA) protocol. The basic access rules of TCMA are similar to CSMA with the following differences: transmission deferral and backoff countdown depend on the priority classification of the data. A station still waits for an idle time interval before attempting transmission following a busy period, but the length of this interval is no longer equal to DIFS. The length of an idle time interval is equal to the Arbitration-Time Inter-Frame Space (AIFS), which varies with the priority of the data. A shorter AIFS is associated with higher priority data. As a consequence, higher priority data gets to the channel faster. In addition, countdown of the backoff timer does not commence when a busy period completes unless the channel has been idle for a period equal to AIFS. This causes backoff countdown of lower priority frames to slow down and even freeze if there are higher-priority frames ready to transmit, a common occurrence in congestion.
The proposed EPCF maintains multiple traffic queues at the stations for different traffic categories. Higher-priority frames are scheduled for transmission first. Delays are reduced through improved polling-list management. Only active stations are kept on the polling list. A station with data to transmit must reserve a spot on that list, where it stays as long as it is active and for a limited number of inactive polling cycles. In the proposed draft standard, the reservation occurs inside the CFP, using a multi-channel ALOHA channel access mechanism to forward reservation requests. A priority mask is available to restrict contention by priority in case of congestion. Several of the features in EPCF are part of the MediaPlex protocol.
The hybrid coordination function (HCF) has been proposed to provide a generalization of PCF. It allows for contention-free transfers to occur as needed; not necessarily at pre-determined regular repeat times as provided by the PCF. The AP can thus send (and possibly receive) data to stations in its BSS on a contention-free basis. This contention-free session, referred to as a contention-free burst (CFB), helps an AP transmit its traffic, which is typically heavier in infrastructure cells (since stations must communicate exclusively through the AP). As in the case of the PCF, the HCF permits access to the channel by the AP after waiting for an idle period of length equal to PIFS.
Attention has also been given by the study group to the problem of co-channel overlapping BSSs (OBSSs). Channel re-use in multiple-cell Wireless LANs poses a problem for the PCF and HCF, as contention-free sessions (CFSs) are generated without coordination among co-channel APs to help prevent time overlap. Some mechanism is needed in situations where cells are within interference range of each other. The existing standard does not provide adequate coordination for contention-free sessions in such situations. The DCF mechanism does not require special measures, as stations operating under the DCF mechanism deal with interference from stations in other cells in exactly the same manner as they deal with interference from stations in their own cell.
All stations within the cell operate on one duplex TDD channel, with only one station in each cell transmitting data at any given time. In order to preserve power, stations go into a sleeping mode, which prevents frequent changes of the operating channel. Channel assignments should thus be fixed or static. Static assignments permit slow adaptation to traffic pattern changes over the course of a day. Ideally, these fixed or static assignments must be made optimal through the use of fixed or adaptive non-regular channel assignment methods, which are based on measurement-derived re-use criteria known in the art. With such an approach, statistical interference relationships between cells are established from measurements of the signal strength between stations and APs in different cells. Optimization methods use these relationships to assign the available channels to cells. Ad hoc channel assignment methods, like Dynamic Frequency Selection of HiperLAN2, can be used but with less promising results, as the re-use distances between co-channel cells are not selected optimally.
The limited number of channels available in the unlicensed band (three channels for IEEE 802.11b) will lead to a high degree of overlap in the coverage areas of co-channel cells. This overlap is exacerbated by the ad hoc placement of wireless LANs that results in overlapping BSAs. The channel time (or bandwidth) must thus be allocated among multiple co-channel cells in order to avoid interference. To be efficient, the channel should not remain idle if there is data waiting for transmission. Thus, while channel selection must be fixed or static, bandwidth allocation should be dynamic (possibly changing on a per-transmission basis).
A distributed dynamic bandwidth allocation mechanism is simply a distributed contention-based MAC protocol, which must enable sharing of the channel among APs and DCF stations in co-channel cells, as HCF and DCF co-exist. With APs accessing the channel to initiate contention-free sessions (CFPs or CFBs) before DCF stations, a prioritized distributed MAC protocol is needed. Such a protocol would also handle different priority DCF data.
The priority-based distributed MAC protocol for EDCF, TCMA, can be used to allocate the channel time among co-channel cells in a multiple-cell wireless LAN. The APs would be treated as a class with priority above the highest DCF priority class and would be assigned, therefore, a shorter AEFS than the highest-priority EDCF data. Other variations of CSMA are also appropriate.
In general, a carrier-sense-based MAC protocol would help avoid interference between cells as it causes conflicting transmissions—either DCF transmissions or CFSs—to occur at statistically (or deterministically, depending on the protocol) different times in co-channel cells.
The objective of dynamic bandwidth allocation is to promote fair access to the channel for all co-channel cells. That is, the success rate of a cell in accessing its assigned channel, either by its AP generating CFSs or by (E)DCF transmissions, should be independent of its location, assuming comparable traffic loads. Without fair access, transmissions can be delayed excessively in the disadvantaged cell, thus failing to meet QoS requirements. This goal is not realized with a traditional CSMA-type of protocol, however, when channel re-use is allowed because of a neighborhood capture effect.
Neighborhood capture arises when Ethernet-type protocols are employed in multiple-cell wireless LANs that re-use radio frequency (RF) channels. Given the small number of channels available, co-channel cells cannot all transmit simultaneously without causing interference on one another. A carrier-sense contention-based MAC protocol can allocate channel bandwidth among co-channel cells dynamically and in a distributed manner; but if used in the conventional way, it may lead to channel capture. Mutually non-interfering co-channel neighbors could deprive other co-channel neighbors of access. In general, there will be instability, with the channel retained by a group of cells for long time intervals. This would have negative impact on quality of service (QoS).
Neighborhood capture arises in a multiple-cell wireless LAN with fewer channels available than the number of cells. Unlike in cellular communications networks, where sufficient channels are available to ensure interference-free transmission on an assigned channel, channel selection in WLAN networks must be accompanied by dynamic bandwidth allocation in order to avoid interference between co-channel cells.
Carrier-sense multiple access (CSMA)-type media access control (MAC) protocols provide dynamic bandwidth allocation in a distributed manner, obviating the need for a central controller. With such protocols, time-overlapped transmissions by stations in non-interfering co-channel cells cooperate to capture the channel for long time periods. The resulting neighborhood capture is deleterious to QoS because of the ensuing access delays in other co-channel cells.
The present invention addresses neighborhood capture and establishes a method to prevent its occurrence.


An IC socket includes a socket body having a plurality of contacts arranged in such a manner as to contact terminal members of an IC package. A contact shutter member is vertically movably mounted on the socket body and adapted, when lowering, to push the contacts against their elastic property so that the contacts will be displaced backward and downward to remove the contact relation. A contact shutter device in the IC socket is characterized by each of the contact having a contact piece portion extending upward from a fixedly embedded portion thereof through a curved spring piece, a cantilever arm extending backward from the contact piece portion, the cantilever arm being provided with a pressing force receiving portion formed on a free end portion thereof and pushed down by the contact shutter member, and a push-start point of the pressing force receiving portion by the contact shutter device being set to a position which is higher than a contact point of the contact piece portion with respect to the terminal members.

1. Field of the Invention
This invention relates to an improvement on a contact shutter device in which contacts are pressed as to be displaced backward and downward by a lowering movement of the contact shutter device mounted on a socket body in order to cancel a contact relation with an IC package.
2. Brief Description of the Prior Art
In Japanese Utility Model Early Laid-open Publication No. Sho 62-111673, the contact is provided with a contacting piece portion formed on an upper end of a curved spring piece, and this contacting piece portion is pressed so as to be displaced backward and downward by the lowering movement of a contact shutter member so that its contact relation with a terminal member of an IC package would be broken.
The above-mentioned prior art aims at mounting and removing the IC package with ease by displacing the contacting piece portion of the contact backward and downward and bringing it to a position where the contacting piece portion of the contact would not interfere with the terminal member of the IC package to release the restraint of the IC package. With the above-mentioned construction of the prior art, however, a lot of useless components of forces for vertically pushing down the contacting piece portion are generated when the contacting piece portion is pushed down, and the push-down force cannot be favorably converted to a backward and downward displacement of the contact. The curved spring piece does not effectively contribute to the backward and downward displacement of the contact. Moreover, there is a fear that excessive generation of components of the vertical push-down force causes the contact to be deformed.
It also has problems such as the excessive push-down force to the shutter member jeopardizing the smooth operation of the device.
There is also proposed another example wherein the contact is provided with a pressing force receiving portion by a contact shutter member projecting from a waist portion below the contacting piece portion of the contact, as disclosed, for example, in Japanese Patent Early Laid-open Publication No. Sho 62-93964. However, as the rigidity becomes extremely high on the side of the contact which is fixedly embedded, the push-down operation of the shutter member becomes very heavy for a socket having many poles, and a space for inserting the push-down portion of the shutter member deep into the back of the contact is required, thus resulting in a large size of the device.


The invention relates to a vehicle seat having a roller guide which has at least one guide rail which is at least partially sideways open and at least one running roller rolling in the guide rail, connected to parts of the vehicle seat via an axle member, wherein a running surface of the running roller is rollable along a roller-underside inner wall of the guide rail arranged parallel or at an angle to a middle axle of the running roller, wherein the running roller comprises at least a first area and a second area, wherein the first area forms at least a part of the running surface and the second area is arranged in a radial direction of the running roller at least partially between the axle member and the first area and in contact with both. According to the invention, an electrical conductivity of the first area is lower than an electrical conductivity of the second area.

Roller guides for vehicle seats, in particular for the rolling of running rollers which are connected to a scissor frame which expands forwards and backwards in the forward and backward direction as the vehicle seat swings up and down, and thus requiring rolling of the running rollers within the guide rail, are widely known.
It is also known that running rollers wear out after a certain operating time. In particular, the running surface of the running roller, that is, the area that forms contact with the running rail when rolling in the running rail, is worn down by material abrasion. The consequence being that the outer diameter of the running roller becomes smaller and is therefore no longer aligned with the dimensions of the running rail. This may cause running noises and play; the running roller rolls, so to speak, "unround" within the guide rail. In addition, there is a risk of further damage to the members of the roller guide up to the breakage of the running roller and/or complete failure of the arrangement.
Due to the fact that the running roller rolls within the guide rail and is accordingly inaccessibly built in, there is also the problem that a pure visual inspection is not easily possible without dismantling the roller guide.


A method of content sub-item substitution is described. The method includes: receiving from a headend a description of a plurality of virtual channels, the description defining each virtual channel on the basis of one or more metadata attributes associated with that virtual channel; receiving one or more content sub-item substitution opportunities for each virtual channel, each content sub-item substitution opportunity specifying one or more content sub-items for use in the content sub-item substitution; and receiving and recording a content item, the content item including metadata associated with the content item and one or more substitutable content sub-items. The method further includes, upon playback (201) of a previously recorded content item: matching the metadata associated with the previously recorded content item with the one or more metadata attributes, thereby determining a virtual channel (205) valid for the previously recorded content item; selecting a content sub-item substitution opportunity (207) based on the determined virtual channel; and substituting the one or more substitutable content sub-items (211) with content sub-items specified in the selected content sub-item substitution opportunity. Related apparatus and methods are also disclosed.

Audio video content is typically broadcast with breaks filled by advertisements. The amount of live television that users are watching is decreasing in favour of recording content on a digital video recorder (DVR) for later viewing. When content is recorded, the advertisements that fill the breaks in the content are also recorded. However these advertisements can be more relevant at the time of the original broadcast than at the time of playback. This is especially true if the recorded content is played back some time after the original transmission of the content.
Advertisement substitution is a technique that uses business rules to target advertisements to individual subscriber homes in a pay TV network. Instead of all viewers receiving the same live channel advertisements, each subscriber is shown targeted advertisements. The targeting is based on a number of factors, often including the original broadcast channel, the genre of the content the substitution opportunity is contained within and the time of day advertisements can be shown.
Operators do not know what content has been recorded by a user and is being stored on disk for later viewing. Therefore, for advertisements in recorded content, advertisement substitution has typically been done using an intelligent agent within the user's DVR, which uses various criteria to determine what advertisement(s) should be substituted within an advertisement substitution opportunity.


A fluid receptacle which includes a low profile reservoir having a first peripheral surface, a second peripheral surface substantially perpendicular to the first peripheral surface and a third peripheral surface substantially parallel to the first peripheral surface and substantially perpendicular to the second peripheral surface; a handle connected to the first peripheral surface; a stand connected to the second peripheral surface; an applicator handle coupled to the fluid receptacle; and a lid coupled to the fluid receptacle wherein the lid covers an opening to the tire shaped reservoir. In other embodiments, the low profile fluid reservoir has a tire shape. In yet other embodiments, the receptacle uses a reservoir that does not have a tire shape.

1. Field of the Invention
Embodiments of the present invention generally relate to the containment and administration of fluids. More particularly, the invention relates to a container that stores a fluid and an applicator, temporarily located on the container, for the stored fluid.
2. Description of the Related Art
It has been known in the prior art that various liquid products can be packaged and marketed in containers. Similarly, it is known in the prior art, particularly in the prior art pertaining to cleaning products, such as soaps, lotions, etc., that brushes can be provided to be utilized in combination with various types of cleaning products to assist in removing dirt or grime in cooperation with the cleaning fluid, such as soap, etc. These brushes are sold and provided in a wide variety of shapes and sizes. Most of these brushes include structural features mounted on the surface of the body of the brush, such as bristles, to assist in the cleaning operation.
It is known that, particularly where containers contain soaps or other cleaning instruments, it is desirable to provide the brush along with the container of the cleaning material at the point of sale so that the purchaser acquires both the cleaning liquid and the brush to be used with it in one stop. One such brush/container combination where the brush is stored on the container is disclosed in Holmes et al. (U.S. Pat. No. 6,302,608, issued Oct. 16, 2001) ("Holmes"). However, in the Holmes patent, neither the brush nor the container are designed to allow the brush to be inserted within the container and thereby access the fluid within the container.
Most conventional containers used for applying a tire cleaning solution are equipped with a spray dispenser that is troublesome to use. Such a dispenser takes too many pump actions to spray the tire completely and the slightest wind blows the spray on the vehicle and on the person using the dispenser. It is apparent therefore that the best dispenser for a tire cleaning solution would be in the form of a brush with an associated container.
Other brush and container combinations are known in the prior art. For example, Sexton (U.S. Pat. No. 772,382, issued Oct. 18, 1904) describes a brush holder which also functions as a lid for a paint can or other container. Similar brush/container combinations are also shown in Striban (U.S. Pat. No. 1,086,626, issued Feb. 10, 1914), Lonskey (U.S. Pat. No. 1,098,390, issued Jun. 2, 1914), and Woodruff (U.S. Pat. No. 1,455,158, issued Jul. 19, 1921). Although such prior art brush/container combinations are known they suffer from several disadvantages, such as for example difficulty in use.
The present invention is intended to solve the problems inherent in the prior art and provide a unique and advanced brush/container combination where the brush is insertable into the container.
It is therefore one general object of this invention to provide a brush applicator combined with a container of fluid that will provide a quick and easy access by the brush to the fluid (e.g., access to a tire cleaning solution for application by the brush onto a tire).


A toilet tissue product may include a first cellulosic ply and a second cellulosic ply. Desirably, the first cellulosic ply further includes a single layer and the second cellulosic ply further includes a single layer. At least one ply may have a region that prevents fluid from striking through the tissue product.

During cleaning after urination the amount of tissue used may be highly variable, but generally about 12 to 15 tissue sheets are used per event for absorbing about 1 milliliter of urine. This tissue amount is about 14 times the actual amount needed based upon tissue's absorption capacity. Using this excessive tissue amount prevents urine from striking through the tissue sheet and reaching the user's hand. Unfortunately, this practice results in tissue waste, which expends economic and degrades environmental resources.
Accordingly, a tissue product that has strikethrough resistance may reduce tissue sheet use by allowing the utilization of the entire absorbency capacity of the tissue, thereby reducing tissue consumption rates and waste.


In a method and a system for generation of print images on a carrier material, an actual speed difference is generated in a transfer printing region between an image carrier and the carrier material. A deviation of the actual speed difference from a desired speed difference is determined with aid of a measurement arrangement.

The preferred embodiment concerns a method in which a speed difference is generated in a transfer printing region between an image carrier and a carrier material. The preferred embodiment also concerns a device for implementation of the method.
High-capacity printing systems for printing of a paper web are known from the documents DE 103 38 496 B3 and DE 103 38 497 A1, in which toner images present on the transfer belt are transfer-printed onto the paper web at a transfer printing point. The drive speed of the transfer belt is preset somewhat greater than the transport speed of the paper web, whereby a speed difference is present between the paper web 12 and the transfer belt. The speed difference is advantageously in the range from 0.1% to 10%, in particular in the range from 0.5% to 3% given a printing speed from 0.9 to 2 m/sec.
A printing system for printing of an endless paper web is known from the document U.S. Pat. No. 6,068,172, which printing system has a device for length compensation of a paper web to be printed in order to generate a preset tensile stress of the paper web in a transfer printing region.
A method and a device for transport of a web-shaped recording medium are known from the document DE 198 28 388 C2, in which method and device a length compensation element is provided with which a sensor is functionally coupled in order to determine the speed difference between a transport device arranged before the length compensation element and a transport device arranged after the length compensation element.
From the document U.S. Pat. No. 6,246,856 B1 a high-capacity printer and high-capacity copier is known in which toner images are generated that are transferred onto a recording medium. A plurality of developer stations are arranged along a photoconductor belt for generation of multi-color toner images, via which developer stations the color separations of a multi-color toner image are generated. The generated toner images of the color separations are successively transferred onto a transfer belt, whereby the individual color separations are thereby printed atop one another in registration. The color separations are thereby collected on the transfer belt. In a feed module what is known as a loop snag is provided via which the tensile stress of the carrier material to be printed is kept relatively constant.
A correct speed difference between the transfer belts serving as image carriers or the transfer belt serving as an image carrier and the carrier material to be printed is a decisive variable for the quality of the transfer printing of toner images onto the carrier material. If the speed difference is too great or too small, disruptions in the print image (for example what are known as wipes) arise or, for example, folds are formed in the carrier material to be printed. The carrier material can flutter in the region before the transfer printing point due to such folds, whereby the transfer printing conditions in the transfer printing region vary continuously. The actual speed difference does not remain constant due to various tolerances of arrangements for direction and propulsion of the carrier material as well as for direction and propulsion of the image carrier as well as variations of the direction and of the propulsion of the image carrier and of the carrier material during the print operation. The speed difference cannot be set or maintained exactly both over a longer image generation process and due to aging and/or wear of components of a printer or copier.

Method and device for detection of the speed difference between an image carrier and a carrier material


In a first aspect, the present invention is a method, apparatus, and system for detecting a change in position of a door or a window in an alarm system with a singular housing having a magnetometer for monitoring the magnetic field of the earth, and a microprocessor for detecting a change in the position of the singular housing with respect to the magnetic field of the earth. The microprocessor generates an alarm signal upon detecting the change, and causes the alarm signal to be transmitted, by wireless transmission, to a remote receiving station. The device may also be used to determine if an object that it is affixed to has been moved, such as for a theft alarm for an object such as a painting. In a second aspect of the invention, a gravitational sensor is used to monitor the gravitational field of the earth and determine if an associated object or person has been moved with respect to the gravitational field, thus providing motion detection and signaling an alarm.

This invention relates generally to the use of a single housing detector device for sensing movement of the device and signaling an alarm signal in a security system, and in particular, in a first aspect, to a single housing wireless sensor that detects a change in the position of a door or window to which the housing is attached by detecting a change in the magnetic field of the earth. In a second aspect, an alarm device senses changes in position of the housing with respect to the surrounding gravitational field in order to trigger an alarm in a security system.
Conventional door or window sensors in security systems contain two housings; one housing with a magnet, and one housing with a sensor such as a reed switch, which is a miniature encapsulated switch that is activated by a magnetic field. One of the housings is mounted to the door or window (entrance closure) being monitored and the other housing is mounted to the doorjamb or windowsill associated with the entrance closure being monitored. When the entrance closure is closed and the magnet is in close proximity to the reed switch sensor, the sensor produces an output signal that indicates that the door is in its closed position. Once the entrance closure is moved the magnet is not in close proximity to the reed switch sensor and the sensor produces an output signal that indicates the door is not in its closed position. The output signal is periodically read by the alarm system controller, and when the signal indicates that the door is not in its closed position, the alarm system controller activates an alarm condition. The alarm system controller may receive this information through wired or wireless transmission. Alarm systems of this type are described in U.S. Pat. Nos. 4,677,424; 4,339,747; 3,896,427; 3,668,579; 4,359,719; and 4,241,337.
Alarm systems using reed switch sensors, as described above, are reasonably successful in many applications, although there are a number of drawbacks as follows:
1) There is additional cost and time, during installation, for the installer to mount a second device (i.e. the magnet).
2) The position of the magnet in conjunction with the sensor is often critical and the installer spends time shimming and locating the magnet to optimize the reed to magnet gap.
3) Reed switches, which are glass encapsulated switches are fragile and may be damaged at the time of installation.
4) Sensors with two housings can be defeated during the period when the system is in the disarmed state by the addition of an extra magnet taped to the sensor housing. This maintains the reed in its closed position even if the door is opened during an armed state.
It is therefore an object of the design to deliver improved security to the system, since any attempt to tamper with the device by adding a magnet would cause an alarm condition.
It is therefore an object of the present invention to provide an entrance closure sensor that is contained in a single housing.
It is a further object of the present invention to provide an entrance closure sensor with improved sensor reliability.
In another aspect of the field of motion detection, sensors designed for asset protection monitor the asset""s location to determine if it is where it should be. If it is determined that the asset is not where it should be, an alarm signal is annunciated. The asset could be an object or a person. For the object, such as a laptop computer, protection would be to determine that the computer has not left the premises without authorization. For a person, such as a firefighter or elderly relative, protection would be to determine that the person was still upright and moving when they should be.
Others have developed devices to perform this task but these devices are either overly complex, expensive, unreliable, or difficult to use. One such device tracks objects by monitoring a marker affixed to the object that periodically sends RF identification signals. Sensors installed at the perimeter of the protection zone detect a breach of the perimeter when the object marker passes the sensor. Disadvantages of this system include short battery life due to the repetition rate of the transmissions and non-detection of the alarm if the asset is hidden within the premises. Another such device is a pendant worn by a person to be protected. If the person feels threatened or becomes ill they press a button on the pendant to annunciate the alarm. A disadvantage of this system is if the person becomes disabled and is unable to press the button, no alarm will be annunciated. Another device similar to our invention uses a dual-axis accelerometer mounted in a notebook PC card that monitors the motion of the PC. If the PC travels a certain distance the PC is disabled. This system differs from ours because it is not wireless, it is not battery powered, there is no alarm annunciation, and its detection method is based the acceleration due to on motion, not the gravitational attraction to the Earth as in our invention.
It is therefore a further object of the invention to provide a device that can sense the movement of an object or person with which the device is associated; i.e. by attachment.
In accordance with these and other objects, the present invention in a first aspect is a method, an apparatus, and a system for detecting a change in position of an entrance closure in an alarm system, wherein the entrance closure is either a door or a window.
The method of this first aspect of the invention comprises the steps of attaching a singular housing on an entrance closure; monitoring, with apparatus in the housing, the magnetic field of the earth, detecting a change in the position of the housing with respect to the magnetic field of the earth, generating an alarm signal upon detecting a change in position of the housing with respect to the magnetic field of the earth that exceeds a first predetermined threshold, and transmitting by wireless transmission the alarm signal to a remote receiving station.
The apparatus of this first aspect of the invention comprises a singular housing with means for monitoring the magnetic field of the earth, means for detecting a change in the position of the housing with respect to the magnetic field of the earth, means for generating an alarm signal upon detecting a change in position of the housing with respect to the magnetic field of the earth, and means for transmitting by wireless transmission the alarm signal to a remote receiving station. The alarm signal may contain a programmable unique transmitter identification number that allows the receiving station to decipher which sensor has sent the alarm message. The monitoring of the magnetic field of the earth is performed by a magnetometer that senses the earth""s magnetic field and generates an output signal correlated to the earth""s magnetic field. A microprocessor detects a change in the position of the housing by sampling the magnetometer""s output signal at predetermined intervals and determining if the sampled output is different from a stored static (initial) output. If the sampled output is different from the stored static output by a first predetermined amount the microprocessor generates an alarm signal and causes the alarm signal to be transmitted. In addition, if the sampled output is different from the stored static output by a second predetermined amount, the microprocessor generates a trouble signal, wherein the second predetermined amount is less than the first predetermined amount. This may occur when the door or window is slightly ajar. This feature is useful to a user during arming of the alarm system, wherein the user can ensure the entrance enclosures are closed prior to vacating the premises being monitored.
The alarm system of this first aspect of the invention comprises the apparatus described above for detecting a change in position of an entrance closure, and a receiving station, located remotely from the apparatus. The receiving station comprises means for receiving by wireless transmission the alarm signal from the apparatus, and means for indicating an alarm condition in response to the receipt of the alarm signal.
The step of detecting a change in the position of the housing with respect to the magnetic field of the earth may take place on three axes and the generation of an alarm signal may occur upon detecting a change in position of the housing in two of the three axes.
In order to provide security with less false alarms, the remote receiving station may correlate the alarm signal from the apparatus of the present invention with a second alarm signal from a different sensor, which may be a motion sensor.
In a second aspect of the invention in this field of motion detection, a sensor that detects changes in the earth""s gravitational field is used to detect motion. The method comprises the steps of locating a housing with respect to an object; monitoring, with apparatus in the housing, the gravitational field of the earth; detecting a change in the position of the housing with respect to the gravitational field of the earth; generating an alarm signal upon detecting a change in position of the housing with respect to the gravitational field of the earth that exceeds a first predetermined threshold, and transmitting by wireless transmission the alarm signal to a remote receiving station.
The housing is located with respect to the object, for example, by affixing the housing to the object (such as by attaching it to a valuable painting, a laptop computer, etc.). The housing may also be hung from an object, such as by placing it on a chain around a person""s neck, or around the person""s wrist, etc.
The apparatus of this second embodiment comprises a housing with means for monitoring the gravitational field of the earth, means for detecting a change in the position of the housing with respect to the gravitational field of the earth, means for generating an alarm signal upon detecting a change in position of the housing with respect to the gravitational field of the earth, and means for transmitting by wireless transmission the alarm signal to a remote receiving station. The alarm signal may contain a programmable unique transmitter identification number that allows the receiving station to decipher which sensor has sent the alarm message. The monitoring of the gravitational field of the earth is performed by a device that senses the earth""s gravitational field and generates an output signal correlated to the earth""s gravitational field. A processor detects a change in the position of the housing by sampling the output signal at predetermined intervals and determining if the sampled output is different from a stored static (initial) output by a predetermined amount. If the sampled output is different from the stored static output by a first predetermined amount the microprocessor generates an alarm signal and causes the alarm signal to be transmitted. In addition, if the sampled output is different from the stored static output by a second predetermined amount, the microprocessor generates a trouble signal. The second predetermined amount may be less than the first predetermined amount.

Method and apparatus for detection of motion with a gravitational field detector in a security system


A memory module, such as a SIMM or DIMM, is provided which incorporates error correction circuitry. The error correction circuitry identifies and corrects errors in communications between the memory module and an external processor. A reliable data processing system is also provided, incorporating the memory module comprising the error correction circuitry with a processor. The yield of manufactured chips is increased by presorting the memory chips which make up the memory module, such that a chip with one or more defective cells may be included in a memory module so long as no other chip has defective cells at the same location.

The present invention relates in general to memory modules, and particularly to methods and apparatus for implementing error correcting code separate from the memory circuits in memory modules.
Systems for storing and recalling information have been developed over the years in conjunction with the advances in computing technology. One of the primary considerations in architecting these memory systems is the ability to accurately read the incoming information and reproduce it correctly when writing it out again. Such electronically-represented information is comprised of a series of bits, each bit having a total of two possible states. It is recognized that a change in the value of a single bit can greatly affect the outcome of a mathematical operation or the meaning of the recorded information. Completely error-free transmission is as-of-yet unattainable. Data errors introduced during transmission, however, can be greatly reduced by the use of parity bits. Simply described, additional bits are added to the string of data bits in a predetermined pattern such that if an error is later introduced the error is detectable and often able to be corrected by logic at the receiving end. One of the better-known codes employed to provide such an error management system developed by R. W. Hamming and is referred to as Hamming code. In its simplest form a message is divided into fixed-length blocks of bits where some of the bits are data bits and the rest of the bits are check bits which are set according to the Hamming code pattern. The ratio of data bits to check bits is such that in any one block any double-bit error can be detected and all single-bit errors are corrected.
There is a cost associated with the described error management process. The standard method of implementing such error correcting code in memories is to incorporate error correction code in the memory circuitry. This type of implementation results in a reduction in amount of memory available for data because of the increased overhead necessary to manage the check bits. For example, each thirty-two bit data word requires an additional seven bits to hold the verification code, necessitating a thirty-nine bit wide memory. Thus the commonly-used thirty-six bit wide single in-line memory module (SIMM) is not available to be used, although this is a conventional and popular size SIMM. In addition, SIMMS are typically created using memory modules that are four, eight, nine, sixteen, or eighteen bits wide. As a result the amount of memory required must be selected as multiples of these sizes. This may require extra memory space to store differently configured memory. This phenomenon was noted by Stanley Wolf, Ph.D. in Silicon Processing for the VLSI Era (1990). Wolf noted that the addition of parity bits imposed a memory area penalty, requiring up to 27% more memory cells to store the same amount of data.
Different approaches have been taken to address this limitation. One known method is to provide the additional space for the check bits, and accept the increased cost in non-standard SIMMS and reduced amount of area available for memory as a trade-off for reliable data. Other methods add circuitry to the memory device itself. An example of this method is shown in U.S. Pat. No. 5,481,552, entitled xe2x80x9cMethod and Structure for Providing Error Correction Code for 8-byte Data Words on SIMM Cardsxe2x80x9d, and issued to Aldereguia et al. Aldereguia discloses a method of associating a system of latches with a memory such that the check bits for each data word are stored separately from the data bits. The system described by Aldereguia allows the conventional 36-bit SIMMS to be used, but doubles the number of memory reads or writes for each data access. U.S. Pat. No. 4,926,426, issued to Scheuneman et al. and entitled xe2x80x9cError Correction Check During Write Cyclesxe2x80x9d, discloses another method of incorporating error correction code in memory devices. Scheuneman describes coupling an error checking and correction circuit with the output means within a dynamic random access memory such that errors may be detected during the read and write cycles. Both of these applications place additional circuitry within the already crowded memory device itself. There remains a need for an error correction system which does not impinge on the valuable real estate of a memory device and which has minimal impact on the speed of memory accesses.
The present invention teaches a method and apparatus for providing reliable communication between a processor and memory devices. What is provided is a memory module comprising a plurality of independently addressable memory devices, a communication path for bi-directional data communication between the driver unit and an external processor, and error correction circuitry electrically located between the driver unit and the communication path. According to one embodiment a driver unit is connected to the plurality of independently addressable memory devices and control signal inputs. In another embodiment the error correction circuitry is incorporated into the driver unit.
In one embodiment the memory module includes a circuit board to which the memory devices are affixed. Another embodiment of the present invention comprises a processor and a memory module comprising error correction circuitry. In a further embodiment the error correction circuitry detects errors in communications between the memory module and an external processor. In another embodiment the error correction circuitry corrects errors in communications between the memory module and an external processor.
According to one embodiment of the invention the plurality of memory devices comprise dynamic random access memories (DRAMs). In another embodiment the plurality of memory devices comprise static random access memories (SRAMs). One embodiment provides memories which are directly mounted on the printed circuit board and environmentally encapsulated. Another embodiment provides memories which are wire-bonded to a lead frame and then encapsulated in plastic, the packaged memory devices then being electrically connected to the circuit board.
Another feature provided by the present invention is chip yield enhancement. In one embodiment of the present invention, the memory devices are sorted before they are included in the memory module, such that there is zero correlation of failing bits among the memories in any one memory module. Also provided is a method of populating a memory module, the memory module having a plurality of independently addressable memory devices and error detection circuitry. The method comprises the steps of testing individual memories to determine locations of defective cells, selecting a plurality of the individual memories such that there is no coincidence of the locations of defective cells among the selected plurality of individual memories, and mounting the selected plurality of individual memories on the memory module such that the error detection circuitry is electrically located between the plurality of memories and an external processor. By this method and system less-than-perfect memory devices are productively used rather than having to be discarded.
A method of error-free communication with a memory module is also provided, the memory module comprising a plurality of independently addressable memories and error correction circuitry. This method comprises the steps of transmitting a write request message to a memory module from a processor, the message information comprising blocks of bit strings, receiving the message at the memory module, modifying the message by appending check bits to each of the blocks of bits, and multiplexing the modified message to the memories. Further steps of this method comprise a memory module receiving a read request from a processor, demultiplexing the requested message from the plurality of independently addressable memories, using the appended check bits to verify the requested message and to correct the message if an error has been introduced, and transmitting the verified message to the processor which issued the read request.

Error correction chip for memory applications


An ink jet printer having a mechanism to restore the nozzles by suction, thereby preventing the contamination of the nozzles of a printing head caused by waste ink and the mixing of color of ink. The ink jet printer is provided with an air releasing unit used to release a cap chamber equipped below the printing head by a cap of a capping unit. While ink droplets are discharged from the nozzles of the printing head, nozzle suction is performed and the cap chamber is released to the atmosphere through the use of the air releasing unit.

1. Field of the Invention
The present invention relates to a serial-type ink jet printer and more particularly to an ink jet printer so configured that printing functions of a printing head are restored by sucking out thickened ink, dust and the like from a clogged nozzle through the use of negative pressure.
2. Description of the Related Art
A conventional serial-type ink jet printer is known wherein ink is discharged from a nozzle formed on a nozzle forming face of a printing head to perform printing.
In the conventional ink jet printer of this kind, image information covering one line is printed on paper while a printing head scans to and from once or more than one time in the direction of the width and, when the printing covering one line is terminated, it is started on a new line again by scanning in the direction of the width.
The ink jet printer can provide printed images with high quality and has an advantage that its printing head produces comparatively less noise while being printed.
However, the conventional ink jet printer presents a problem in that a nozzle of the printing head, when not in use, may get clogged up with dried ink, dust and floating materials in the air. Solidified ink, adhered dust and the like may cause defective discharging of ink (so-called "dot omission") and interfere with normal printing. To prevent this, when the nozzle is not in use, the printing head is taken off from the ink jet printer to be housed in a keeping box or a nozzle forming face of the printing head is sealed to prevent drying of ink, adherence of dust and the like. However, it is inconvenient for a user to take the printing head off from the ink jet printer and to house it in the keeping box in every use and, in many cases, such storing of the printing head in the keeping box is not put into practice accordingly.
Another method for solving the problem of clogging of the nozzle of the printing head is to provide the ink jet printer with a nozzle restoring mechanism in which printing functions of the printing head are restored by using suction processes.
The conventional nozzle restoring mechanism is so configured that caps surrounding a group of nozzles in a closed contact with a nozzle forming face of a printing head are provided and air within a sealed cap chamber formed by the cap and the nozzle forming face is sucked so that solidified ink, dust and the like within the nozzle are sucked out forcedly together with air. The nozzle restoring mechanism, unlike in the case of using the keeping box, has an advantage that there is no need for intervention of users. That is, the ink jet printer is provided with a nozzle restoring section on the side of its printing section and, when the nozzle is not in use, the printing head is automatically brought to the position of the nozzle restoring section.
However, the conventional nozzle restoring mechanism using suction processes presents a problem in that waste ink residing in the cap after the suction has been carried out (or waste ink residing within a path of ink discharged by the suction) invades backward into the nozzle by residual negative pressure within the nozzle of the printing head, causing the nozzle to be contaminated with waste ink.
The influence by the contamination remarkably shows up in a color ink jet printer in particular. Recently, users tend to prefer the color ink jet printer that can provide color printing. In response to these demands, the recent ink jet printer can use multicolor ink and is provided with a printing head with nozzles that can be operated in use with such various color ink. In such a color ink jet printer, if waste ink is present even in trace amounts, it causes a color image to be degraded. Especially, for example, if bright color ink such as yellow ink or the like is mixed with dark color ink such as black ink, the resulting color image decreases in the quality, causing a feeling of visual strangeness.
Such a malfunction caused by the mixing of ink having different components does not always occur only in ink jet color printers. For example, in the case of an ink jet printer using black ink only, the printing head with different specifications uses black ink having different components. In any case, therefore, mixing of ink must be avoided in the operation of printers.


A watercraft has a throttle position sensor, an engine speed sensor, and a start switch. The sensors communicate with a controller. The controller can regulate engine speed. The controller regulates or limits the engine to a low speed when the throttle angle is above a predetermined value during startup, and/or when the engine temperature is too low.

This application is based on and claims priority to Japanese Patent Application No. 2001-027045, filed Feb. 2, 2001, the entire contents of which are hereby expressly incorporated by reference.
1. Field of the Invention
The present application generally relates to an engine control unit, and more particularly, an engine management system that prevents excessive engine speed for a predetermined period of time after the engine has been started.
2. Description of the Related Art
Personal watercraft, like other applications that use internal combustion engines as power sources, are experiencing considerable public and governmental pressure to improve not only their performance, but also their exhaust emissions levels. For example, due to the emissions generated by two-stroke powered watercraft, certain recreational areas have banned the operation of such watercrafts. These bans have decreased the popularity of personal watercraft, and have caused manufacturers of these types of watercraft to consider fuel injected engines to power their watercraft and/or other means to reduce emissions levels.
Fuel injected engines are known to provide significantly enhanced performance, power output, and emission control as compared to carbureted engines. Watercraft, however, normally do not have a neutral setting where the engine is allowed to operate without driving the propulsion device.
One aspect of the present invention includes the realization that often times the operator of a watercraft opens the throttle when starting the engine, even though the engine does not need the throttle to be opened. For example, certain known fuel injected engines can be programmed to start quickly and reliably without any manipulation of the throttle by the user. Excessive opening of the throttle during commencement can be both harmful to the various engine bearing surfaces due to low initial oil pressure and high oil viscosity. Additionally, an abrupt thrust from the propulsion unit caused by unnecessarily opening the throttle can make docking maneuvers more difficult.
Another aspect of the present invention is directed to a method of controlling engine operation during start-up in a watercraft. The method includes sensing a throttle valve angle, and determining if said throttle valve angle is larger than a predetermined throttle valve angle associated with normal engine start-up.
A further aspect of the invention is directed to a method of controlling operation of a watercraft engine during a predetermined engine speed range. The method includes sensing a throttle valve angle, and determining if the throttle valve angle is larger than a predetermined throttle valve angle associated with the predetermined engine speed range
Yet another aspect of the present invention is directed to a watercraft having a hull and an engine supported by the hull. The watercraft also includes, a fuel delivery system, an ignition system, a throttle valve, and a controller configured to control operation of the fuel delivery and ignition systems. The controller is configured to at least partially disable at least one of the fuel injection system, ignition systems, and starter motor if the throttle valve is open more than a predetermined amount.
Another aspect of the invention is directed to a method of controlling operation of a watercraft engine. The method includes detecting a temperature of the engine, detecting a speed of the engine, and at least partially disabling at least one of the fuel delivery and ignition systems if the engine speed is above a predetermined speed and the temperature is below a predetermined temperature.
Yet another aspect of the invention is directed to a watercraft having a hull and an engine supported by the hull. The watercraft also includes a fuel delivery system, an ignition system, an engine speed sensor, an engine temperature sensor, and a controller configured to control operation of the fuel delivery and ignition systems. The controller is also configured to at least partially disable at least one of the fuel injection and ignition systems if a speed of the engine is higher than a predetermined speed and if a temperature of the engine is below a predetermined temperature.

Engine control unit for small watercraft


A method and apparatus to selectively disregard co-channel transmissions on a medium uses an automatic gain control/clear channel assessment (AGC/CCA) circuit to gather signal power information, which is used to establish receiver sensitivity thresholds. Raw and cyclical power measurements of a received signal are processed by the AGC/CCA circuit to determine whether a current received signal process should be halted, and a new signal acquisition sequence begun.

1. Field of the Invention
Embodiments of the present invention generally relate to wireless devices and more specifically to receiving and transmitting signals between transceivers.
2. Description of the Related Art
Generally, a communication system includes a transmitter and receiver, which transmit and receive information signals over a transmission media such as wires or atmosphere. When atmosphere is used, the transmission is commonly referred to as "wireless communication." Examples of various types of wireless communication systems include digital cellular, packet data paging, wireless local area networks (LAN), wireless wide area networks (WAN), personal communication systems and others.
The capacity of a wireless communication system (i.e. the number and density of users that can be serviced) is heavily influenced by co-channel interference (CCI). CCI interference from adjacent access points (APs) and nearby mobiles represents a fundamental issue in system design and deployment. CCI occurs when signals from two access points operating on the same frequency are within a distance that allows the signals to propagate from one AP within one basic service set (BSS) to another AP within another BSS. Because the two signals are on the same channel, each AP allows both signals to pass to its respective baseband processor.
Conventionally, mitigating co-channel interference has been achieved using frequency reuse planning, and other isolation techniques that rely on the wireless medium environment.
One method for mitigating co-channel interference involves increasing the number of frequency channels available for use. When more frequency channels are available, a larger physical distance can be provided between access points using the same channel. This method may work well for wireless networks having access to a large number of channels but not as well for those with a limited number of frequency channels. For example, a wireless network operating in an IEEE 802.11a environment having as many as twelve non-overlapping channels has a distinct advantage over a wireless environment operating in an IEEE 802.11b environment where the number of non-overlapping channels is limited to three. The number of non-overlapping channels available in a given band and a given geographic region depends on government regulations and is usually difficult or impossible to change.
Increasing the distance between each BSS operating on the same channel may be used to allow the propagation loss of the transmission medium to attenuate the interfering signals to low levels. Unfortunately, as access points become denser with the proliferation of wireless devices, distances between access points decrease and thereby increases the likelihood of CCI.
Generally in IEEE 802.11 networks all wireless devices are required to operate according to the distributed coordination function (DCF) rules. All wireless devices and access points operating under these rules must perform a clear channel assessment (CCA) before transmitting. The CCA may result in one BSS waiting for signals intended for another BSS. This is referred to as CCA capture. Due to CCA capture, the available channel capacities from two BSSs operating on the same frequency channel are shared between all of the wireless devices for both BSSs thereby degrading the overall BSS throughput.
Generally, within a single BSS, all wireless devices are usually able to hear one another. However, in the case of multiple BSSs separated by some distance and on the same channel, some wireless devices within one BSS may hear messages from the interfering BSS while others do not. Therefore, the co-channel interference may preoccupy some of the wireless receivers and therefore not allow them to communicate with their own BSS thereby reducing the BSS communication efficiency. This interference may occur even if the signal strength of the arriving signal is lower than the standard-defined CCA threshold. However, once receiving a packet, most devices will attempt to receive the complete packet independent of the signal strength, source, destination or network identification addresses. This is commonly referred to as receiver capture. Both CCA capture and receiver capture may cause the throughput to degrade for some or all of the devices in a BSS. In some circumstance not all devices in a BSS are able to hear co-channel interference. In this case, a device may begin transmission to another device that is already busy receiving a co-channel interference signal.
Therefore, what is needed is a method and apparatus to configure a plurality of; adjacent wireless network circuits to operate simultaneously without reducing communication system efficiency and without increasing cost and complexity.

Method and apparatus for selective disregard of co-channel transmissions on a medium


A high performance ceramic block for use with small-scale circuitry is described. The block can be used in an optical sub-assembly (OSA) suitable for optical interconnection with optical fibers and electrical interconnection with a chip sub-assembly (CSA) is formed. The block includes a first surface and a second surface and is formed using one of low temperature co-fired ceramic (LTCC) and high temperature co-fired ceramic (HTCC) techniques. Photonic devices are formed on the first surface of the ceramic block and electrical contacts are formed on a second surface of the block. The electrical contacts being suitable for electrical communication with a chip sub-assembly. Electrical connections are formed so that they pass internally through the ceramic block to electrically interconnect the photonic devices on the first face of the block with the electrical contacts on the second face of the block. Such a block can be advantageously used to form an optoelectronic module.

The present invention relates generally to techniques for connecting the optical and electrical device components. More particularly, the invention relates to LTCC (low temperature co-fired ceramic) structures for use in optical subassemblies.
Many computer and communication networks being built today, including the Internet, are using fiber optic cabling instead of copper wire. With fiber optic cabling, data is transmitted using light signals, not electrical signals. For example, a logical one may be represented by a light pulse of a specific duration and frequency, a logical zero may be represented by the absence of a light pulse for the same duration. Optical fiber has the advantage of having a much greater bandwidth than copper wire.
While fiber optic cabling is very efficient for transferring data, the use of light signals to process data is still very difficult. For instance, currently there is no efficient way to xe2x80x9cstorexe2x80x9d light signals representative of data. Networks therefore use fiber optics for transmitting data between nodes and silicon chips to process the data within computer nodes. This is accomplished by using fiber optic transceivers, which convert light signals from a fiber optic cable into electrical signals, and vice versa. FIG. 1 illustrates a perspective view of an exemplary optoelectronic module 100 that can be used to form an optical transceiver.
Optoelectronic module 100 includes a semiconductor chip subassembly (CSA) 102 and an optical subassembly (OSA) 104. CSA 102 is a packaged semiconductor device. As shown in FIG. 1, CSA 102 is a rectangular block of molding material 106 that has electrical contacts 108 exposed through its bottom and side surfaces. Within the block of molding material 106 is a semiconductor die that is electrically connected to contacts 108. For instance, wire bonds can be used for such connections. Another aspect of CSA 102 that cannot be seen is the up-linking contacts on the top surface of CSA 102. These up-linking contacts are also electrically connected to the encapsulated semiconductor die and therefore provide the electrical communication between the semiconductor die and OSA 104. The specific CSA 102 that is shown is a leadless leadframe semiconductor package (LLP). However, it should be understood that CSA 102 can be formed of various types of molded packages.
A conventional OSA 104 includes a conventional backing block 110, a circuitry substrate 112, and photonic devices 114. Backing block 110 has a front surface 116 that supports circuitry substrate 112 and photonic devices 114, which are attached to circuitry substrate 112. A conventional backing block 110 can be formed of a variety of materials such as a ceramic material, polyethylene ether ketone (PEEK), or liquid crystal polymer (LCP). Examples of such conventional OSA""s 104 and backing blocks 104 are known to persons having ordinary skill in the art. One typical example of such a conventional backing block is described, for example, in the U.S. patent application Ser. No. 10/165/711, entitled xe2x80x9cCERAMIC OPTICAL SUB-ASSEMBLY FOR OPTO-ELECTRONIC MODULES,xe2x80x9d filed on Jun. 6, 2002.
In conventional implementation, a circuitry substrate 112 is attached to a front surface 116 of backing block 110, wraps around the bottom-front corner of backing block 110, and covers most of the bottom surface of backing block 110. Traces of the circuitry substrate 112 run from photonic devices 114 on the front surface to the bottom surface of backing block 110 where they make contact with the up-linking contacts of CSA 102. In an effort to maximize the number of electrical connections possible, size dimensions of the foregoing devices are small. However, even though the size dimensions are made small, the fact that the circuitry substrate 112 is formed only at the surface (or in some implementations two layers deep) of the backing block 110 limits the overall number of electrical connections that can be made from the photonic devices 114 to contacts of the CSA 102.
Additionally, such surface mounted circuitry substrates 112 can suffer from xe2x80x9ccross-talkxe2x80x9d. In typical implementation, size dimensions involved with circuitry substrate 112 are small and cause the circuit traces to be positioned very close to each other. The small size is advantageous in the same way that small sizes for most electronic devices are advantageous. However, the close proximity of the traces can cause xe2x80x9ccross-talk,xe2x80x9d especially at high operational frequencies. Cross-talk is the electrical interference between two or more electrically conducting elements. Such cross-talk can drastically reduce the performance of optoelectronic device 100.
FIG. 2 is a schematic depiction of a conventional backing block 204 (depicted upside down) showing a bottom side 201 and a facing side 202. Commonly, the photonic devices 214 are formed on the facing side 202 of the block 204 and electrically connected to contact pads 215 on the bottom side 201. The photonic devices 214 are electrically connected to contact pads 215 using surface metallization techniques. Typically, the photonic devices 214 are electrically connected to contact pads 215 using electric traces (or leads) 216 formed on a special contact tape that adheres to the block 204. A problem with this implementation is that the electric traces 216 have a tendency to fail in the region where the tape bends over the edge 217 of the block 204.
In view of the foregoing, what is needed is an efficient technique for forming high density electrical connections from the photonic devices of an optical device to an associated semiconductor chip device such that the connections exhibit high circuit density and low levels of cross-talk.
The present invention is directed to a high performance and small-scale circuitry substrate and supporting block used in optical sub-assemblies. In one embodiment an optical sub-assembly (OSA) suitable for optical interconnection with optical fibers and electrical interconnection with a chip sub-assembly (CSA) is formed. The OSA includes a ceramic block having a first surface and a second surface, the ceramic block being formed using one of low temperature co-fired ceramic (LTCC) and high temperature co-fired ceramic (HTCC) techniques. Photonic devices are formed on the first surface of the ceramic block and electrical contacts are formed on a second surface of the block. The electrical contacts being suitable for electrical communication with a chip sub-assembly. Moreover, the electrical connections being formed so that they pass internally through the ceramic block to electrically interconnect the photonic devices on the first face of the block with the electrical contacts on the second face of the block.
Another embodiment includes a ceramic block having a first face and a second face. The block being formed using one of low temperature co-fired ceramic (LTCC) and high temperature co-fired ceramic (HTCC) techniques. The first face of the ceramic block has at least one photonic device formed thereon. Contact pads are formed on the second face of the ceramic block. The block also includes electrical connections that are electrically connected to the photonic devices and pass through internal portions of the ceramic block to so that the electrical connections can electrically the photonic devices to a chip sub-assembly (CSA). The electrical connections can include both signal connections and ground connections. Moreover, embodiments can include internal shielding layers. The configuration of the block can be designed so that cross-talk is reduced, low levels of ground-bounce and electrical parasitics are exhibited, and optimal impedance levels can be obtained. The circuitry substrate can be advantageously used to form an optical sub-assembly (OSA) used in an optoelectronic module.
In another embodiment, the ceramic block includes a plurality of ceramic layers formed using one of low temperature co-fired ceramic (LTCC) techniques and high temperature co-fired ceramic (HTCC) techniques. The ceramic block includes a front surface and a bottom surface. The front surface of the block includes a plurality of contact pads with a plurality of photonic devices. The bottom surface includes a plurality of solder pads. The block further includes internal electric contact planes having at least one electric contact line formed thereon such that the at least one electric contact line passes internally through the ceramic block and is in electrical communication with the contact pads and associated solder pads. The contact pads having wire bonds for electrically connecting the contact pads with the photonic devices. The block also includes at least one internal ground plane having at least one ground contact line formed thereon such that the at least one ground contact line passes internally through the ceramic block and is in electrical communication with selected solder pads. The module further including a semiconductor chip sub assembly (CSA) having a top surface that has exposed up-linking contacts that are in electrical contact with the solder pads formed on the bottom surface of the ceramic block when the ceramic block is placed onto the top surface of the CSA.
These and other features and advantages of the present invention will be presented in more detail in the following specification of the invention and the accompanying figures, which illustrate by way of example the principles of the invention.

Ceramic optical sub-assembly for opto-electronic module utilizing LTCC (low-temperature co-fired ceramic) technology


An engine system is disclosed in which the transfer of heat from pressurized oil flowing through an integrally formed oil transfer passage of the engine is reduced by providing a thermal barrier between the oil and the engine. In one example the thermal barrier is provided by the use of a thick walled plastic tube and in other embodiments ribs are used to separate an oil flow passage from the engine.

It is well known in the art that following a start-up from cold, that is to say, an engine start-up where the temperature of the engine is close to ambient temperature, significant losses are produced due to the lubricating oil being below an optimum operating temperature. These losses increase fuel usage during the initial warm-up period and in addition wear is increased if the oil is below a minimum temperature at which additives in the oil become fully activated.
Several methods have therefore been previously proposed to either actively heat the oil by the use of electric oil heaters or by heat transfer with the exhaust gas from the engine or by passive heating by recirculating at least some of the oil that has already passed through the engine thereby speeding up the heating of the oil by the use of partitioned oil reservoirs such as that shown in published patent application GB-A-2251889.
It is a problem with all such previous attempts that, although the temperature of the oil may be increased by these measures before it enters the engine, the very large thermal mass of the engine compared to the thermal mass of the oil means results in the temperature of the oil rapidly reducing as it flows through the engine by the transfer of heat from the oil to the engine. Therefore, by the time the oil reaches the key components of the engine requiring lubrication such as the main bearing of the crankshaft its temperature will normally be close to the temperature of the engine components through which it has passed. In addition, the high thermal mass of the engine means that it will take several minutes for the engine to attain its normal operating temperature of approximately 90° C. after a cold start and during this period of time the oil will likely be more viscous and may have lower lubricating properties than are desirable for optimum fuel efficiency. Although this is a particular problem following a start-up from cold it can be a persistent problem with some engines if the oil passages to the bearings are located in a cool part of the engine where the temperature of the engine during normal running of the engine remains below that required for optimum oil operation.

Engine system and a method of manufacturing same