The American Fibertek MT81 is a module transmitter component of the 81 series which multiplexes 8 channels of dry latching contact closure on one multimode fiber. A user-selectable feature allows the contact status to be maintained unchanged or reset through power-cycle and loss-of-optical-power. A reset button is available to clear all contact status to the default state. Individual channel LEDs on the transmitter and the receiver units indicate the channel status. These systems require no field adjustments at installation or additional maintenance thereafter. Diagnostic indicators provide a quick visual indication of system status. Equipment may be ordered as stand alone modules or rack cards that are mounted in the SR-20D/2 or SR-20R/1 AFI Card Cages. The "Afinety" intelligent remote monitoring system is available on the Rack Card product, please consult the factory.