A wireless communications technology in competition with analog cellular services. In an SMR system, the base station equipment supplier is the licensee of the transmitters. Users have access to the multiple channels of the network rather than the limited number of channels of a private mobile radio network. Many users share all of the available channels. Sharing is accomplished on a first-come, first-served basis. When users want to initiate a call, they activate the push-to-talk button on the handset. Assuming the portable unit (and dispatcher or other portable unit) is tuned to an available channel, a communication path is established. If channels that the sender and receiver can use are not available, the call cannot be completed, and the operator must wait for another opportunity to try again.