A communication system is described which provides call queueing between a base station (400) which does not have a control channel and a plurality of portable communication handsets (401). The base station (400) determines when all channels are busy, and following one becoming available, transmits a...http://www.google.com.hk/patents/US5260993?utm_source=gb-gplus-share專利 US5260993 - Queuing apparatus and method for a cordless communication transceiver
