A call initiation request is sent on the reverse control channel (RCC).Mobile unit transmits its telephone number (MIN), Electronic Serial Number (ESN), Station Class Mark (SCM) which indicates power level and telephone number of called party.

The cell BS receives this information and sends it to MSC. The MSC validates the request, makes connection to called party through the PSTN.MSC instructs BS and mobile user to move to an unused voice channel pair to allow the conversation to begin