The paper describes an automatic radiotelephone system design aimed at obtaining maximum utilization from a group of around 100 radiotelephone channel pairs. The system uses a dedicated 'calling' and 'answer' signalling channel pair to manage up to 100 'talk' channel pairs operated as a single trunk group. Talk channels are not assigned until the mobile has answered, and dialed dlgits from the mobile are stored before transmission. The signalllng 'handshakes' between the base and mobile equipment are described together with numbering, coding, synchronization and modulation schemes. The control channel capacity is derived in terms of the offered traffic, and the grade of service considerations are outlined.