User Manual

Psion Teklogix 9160 Wireless Gateway User Manual E-11

Appendix E: Glossary

Ethernet

Ethernet is a local-area network (LAN) architecture supporting data transfer rates of

10 Mbps to 1 Gbps. The Ethernet specification is the basis for the IEEE 802.3

standard, which specifies the physical and lower software layers. It uses the

CSMA/CA access method to handle simultaneous demands.

Ethernet supports data rates of 10 Mbps, Fast Ethernet supports 100 Mbps, and

Gigabit Ethernet supports 1 Gbps. Its cables are classified as “XbaseY”, where X is

the data rate in Mbps and Y is the category of cabling. The original cable was

10base5 (Thicknet or “Yellow Cable”). Some others are 10base2 (Cheapernet),

10baseT (Twisted Pair), and 100baseT (Fast Ethernet). The latter two are commonly

supplied using CAT5 cabling with RJ-45 connectors. There is also 1000baseT

(Gigabit Ethernet).

ERP

The Extended Rate Protocol refers to the protocol used by IEEE 802.11g stations

(over 20 Mbps transmission rates at 2.4GHz) when paired with Orthogonal

Frequency Division Multiplexing (OFDM). Built into ERP and the IEEE 802.11g

standard is a scheme for effective interoperability of IEEE 802.11g stations with

IEEE 802.11b nodes on the same channel.

Legacy IEEE 802.11b devices cannot detect the ERP-OFDM signals used by IEEE

802.11g stations, and this can result in collisions between data frames from IEEE

802.11b and IEEE 802.11g stations.

If there is a mix of 802.11b and 802.11g nodes on the same channel, the IEEE

802.11g stations detect this via an ERP flag on the access point and enable request

to send (RTS) and clear to send (CTS) protection before sending data.