Patent ID: 8055350

Claim:
A method by which an external device communicates with an implantable medical device, comprising: transmitting a data segment containing a repeating sequence of special wakeup characters and a device ID from the external device in order to establish a communications session with the implantable device, wherein a transmitter and receiver of the implantable device are powered up, according to a timed duty cycle, for a specified time window at periodic intervals and waits for receipt of one of the special wakeup characters transmitted by the external device; wherein the implantable device suspends operation of the timed duty cycle and time window, maintains the transmitter and receiver in a powered-up state upon receipt of a special character prior to receipt of the device ID and prior to establishment of a communications session and for as long as consecutive special wakeup characters continue to be received, transmits an acknowledge signal to the external device if the device ID matches an ID of the implantable device, and then waits a specified period of time for a response from the external device; and, establishing the communications session when a response to the acknowledge signal is received by the implantable device.