A mobile telephone power management method and apparatus is disclosed that places the telephone in a dormant, or idle, mode. In this mode, battery power is only supplied to a device incorporated into the mobile telephone that monitors incoming radio frequency (RF) signals. If the device detects an inbound call, the device sends signals to switch on battery power to the mobile telephone baseband microprocessor. The device also sends stored registration information to the baseband microprocessor, thereby allowing the telephone to rapidly switch to active mode, and to answer the inbound call. This method allows the telephone to effectively emulate standby mode for weeks rather than days without the need for battery recharging.