User's Guide

Antennas
207
RF-DLC Base Station / Substation Polling Protocol. To overcome the CSMA/
CA limitations mentioned above, Solectek has developed a base station / substation
polling protocol called RF-DLC. The RF-DLC protocol allows for higher throughput
under heavy load than systems using CSMA/CA or other similar protocols.
The base station allocates substation access to the internetwork. It polls each substation
and allows a designated time for the substation to respond. This polling protocol has
the following advantages:
• To avoid the capture effect where strong stations dominate, the base station
partials out time to substations needing to broadcast.
• If a connection is lost, the disconnected station does not respond to polling.
When a station times out without responding, the connection is recovered.
• Individual substations on the network do not need to listen to each other to
avoid collisions. Since the base station manages all broadcasts, no two substa-
tions can transmit at the same time.