A trunked communication signalling method is provided by a unifying signalling protocol in which subscribers request communication channels using only their individual IDs encoded into a single ISWs. The central decodes the call request, extracts the requesting subscriber's individual ID, which is cross...http://www.google.de/patents/US4723264?utm_source=gb-gplus-sharePatent US4723264 - Signalling method for establishing trunked communication
