Intracranial senceiver

An intracranial senceiver was a device which was implanted into the skull of an individual in order to be able to locate them when they were otherwise incommunicado. In the 2280s, all Starfleet flag officers were required to have intracranial senceivers while serving planetside. Dr. Leonard McCoy, however, hesitated to use this device when trying to track down Admiral Jim Kirk, considering it an invasion of privacy.