e Transactions between stations transmitting data to each other In fact anything sent across the system is split into frames. There are three types of frame. Data frames that are used to send actual data from one station to another, control frames that are used to control the way in which data is sent (examples of these are the RTS, CTS and ACK frames that are sent) and finally there are the management frames. These are sent across the system in the same way as the data frames and they are used to control or manage the cell, but the data is not visible to the user. HomeRF SWAP The HomeRF Shared Wireless Access Protocol (SWAP) is designed primarily for home applications where it is intended to carry both voice and data information for a broad range of interoperable consumer devices. The system is intended for a broad range of items including PCs, peripherals, cordless phones and many other devices to share and communicate voice around the home without the need to run fixed and expensive wiring. Unlike Bluetooth, which is aimed primarily for use with cellular technology, or IEEE802.11 which is intended for business use, SWAP is intended for home use where the developers see a vast and growing market. The system can support data rates of between 10 and 20 Mbps combined with sufficient range for most residential applications. If operating over slightly greater distances the speed can back off to 5 Mbps. Like 802.11b and Bluetooth, HomeRF operates in the 2.4 GHz ISM band. It uses frequency hopping with a hop rate of between 50 and 100 hops per second. The system can be set up in either ad hoc, peer to peer mode, or as a network with a control point (CP) giving access to a wired network within the house. In this respect it has many similarities to 802.11b. 290 Newnes Guide to Radio and Communications Technology Data transmission Voice calls Time allocated to streamed media sessions Figure 11.4 HomeRF data frame structure When requiring to send data the CSMA/CS protocol derived from 802.11 is used. Here the unit wanting