ns using standard telephone lines and delivering data rates of up to 1.5 Mbps. Glossary Directional Antenna: A directional antenna focuses transmitted power into a narrow beam, increasing the range at the expense of reduced angular coverage. Patch, Yagi and parabolic are types of directional antennas. Direct Sequence Spread Spectrum (DSSS): Direct Sequence Spread Spectrum is a data encoding technique in which the input bit stream is XOR'd with a chipping code to increase its bandwidth. On reception, the chipping code sequence is easier to detect in a noisy environment than a single transmitted bit, resulting in an additional gain in the system known as the processing gain. Longer chipping codes result in higher processing gain. Diversity: Diversity refers to a technique for improving the transmission of a signal, by receiving and processing multiple versions of the same trans- mitted signal. The multiple received versions can be the result of signals following different propagation paths (spatial diversity), being transmitted at different times (time diversity) or frequencies (frequency diversity). The simplest example of diversity in practice is the use of diversity anten- nas, where a receiver continuously senses the strength of received signals on two or more antennas and automatically selects the antenna receiving at maximum strength. Dynamic Host Configuration Protocol (DHCP): DHCP is a protocol that automatically provides network addressing and configuration information such as an IP address, sub-net mask and default gateway to a device when it connects to the network. Typically a device retains an assigned IP address for a specific administrator-defined period of time known as the lease period. Dynamic Frequency Selection (DFS): Dynamic Frequency Selection enables wireless networking devices to select a transmission channel to be used in order to avoid interference with other users, particularly radar and medical systems. DFS was introduced in the 802.11h supplement to enable 802.11a WLANs to comply with E