Microstimulator having bi-directional telemetry system

An implantable microstimulator (10) configured to be implanted for tissue stimulation employs a self-contained power source (16) and a bi-directional RF telemetry link (48) for allowing data-containing signals to be sent to and from the implantable microstimulator (10) from at least two external devices (39,40). Further, a separate electromagnetic inductive telemetry link (38) allows data containing signals to be sent to the implantable microstimulator from at least one of the two external devices (39). The implantable microstimulator, comprises: an hermetically-sealed housing (213); a first electrode (22) and a second electrode (24) for stimulating tissue, each electrode external to the hermetically-sealed housing; an antenna (18) within the hermetically-sealed housing; and telemetry circuitry coupled to the antenna for receiving data-containing signals from at least one external device (39,40,60), said telemetry circuitry comprising: a first telemetry receiver for receiving data in accordance with a first telemetry scheme, and a second telemetry receiver for receiving data in accordance with a second telemetry scheme.