Patent ID: 8639339

Claim:
A telemetry system for enabling wireless communications between an implantable medical device and an external remote monitor (RM), comprising: a wireless transmitter, a wireless receiver, and a controller incorporated into each of the implantable medical device and the RM; a wakeup timer incorporated into the implantable device; wherein the transmitter and receiver of the implantable device are interfaced to the controller to enable the transmitter and receiver to be independently powered up or down; wherein the RM is programmed to transmit a data segment containing a repeating sequence of special wakeup characters in order to establish a wireless communications session with the implantable device; wherein the implantable device is configured to: power up its receiver for a specified time window at periodic intervals to wait for receipt of a special wakeup character transmitted by the RM; maintain its receiver and place its transmitter in a powered-up state upon receipt of the special character and for as long as consecutive special wakeup characters continue to be received; and transmit an acknowledge signal upon receipt of at least one character other than a special wakeup character; and wherein the RM is configured to: establish a communications session with the implantable device when a response to the acknowledge signal is received by the implantable device; and adjust a periodic interval at which the RM transmits the special wakeup characters to the implantable device according to when previous successful communications sessions have been established.