Abstract: A method and apparatus for passively monitoring communications in a trunked communication system. Digital messages transmitted over a control channel at a particular frequency are monitored with a receiver. When a first bit pattern is detected in a digital message, subsequently transmitted data is stored. Information is extracted from the stored data to obtain a channel assignment code indicating a frequency over which communications take place and a talk group identification code identifying a talk group in the trunked communication system participating in a communication. If the talk group is a talk group of interest, the receiver is tuned to the frequency corresponding to the channel assignment code so that voice communications are successfully monitored.