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...http://www.google.ca/patents/US20030114897?utm_source=gb-gplus-sharePatent US20030114897 - Implantable medical device with two or more telemetry systems
