A method of testing optical network equipment involves plugging a tester device into a standard electrical socket on the optical network equipment to be tested. The tester device communicates with the optical network equipment to be tested via the standard electrical socket, appearing to the optical network equipment as though it was an optical transceiver that would be plugged into the standard electrical socket in normal use. The tester device thus has a plug with the same physical and electrical properties as the optical transceiver, and uses the same electrical signaling protocols and or formats that are used by the optical transceiver.