A telemetry system enabling radio frequency (RF) communications between an implantable medical device and an external device, or programmer, in which the RF circuitry is normally maintained in a powered down state in order to conserve power. At synchronized wakeup intervals, one of the devices designated as a master device powers up its RF transmitter to request a communications session, and the other device designated as a slave device powers up its RF transmitter to listen for the request. Telemetry is conducted using a far field or near field communication link.