An ad-hoc, peer-to-peer radio system includes a series of radio terminals forming a service group, each radio terminal having a transceiver for communicating with terminals in the same service group, computer means, and memory for storing program software. Within the system, a method and protocol for communication among the terminals includes establishing a connection with one radio terminal based on time-division access; initiating an outgoing call from the radio terminal including registering with another radio terminal for serving as a node in the call connection by transmitting a registration request; and initially transmitting said registration request on a last time slot (TS) of a respective time frame (TF), said last time slot serving as a configuration channel.