A telemetry system and method of downhole communication is disclosed. A first electromagnetic signal propagates through a first annular region between a work string and a wellbore wall and is received at an electromagnetic receiver of a repeater. A second electromagnetic signal related to the received first electromagnetic signal is created at a processing unit coupled to the electromagnetic receiver. The second electromagnetic signal is transmitted from a transmitter of the repeater into a second annular region between the work string and the wellbore wall. The repeater may be detachably coupled to the work string and may facilitate communication between a first communication device at one of an uphole location and a downhole location and a second communication device at another of the uphole location and the downhole location.