MPA means MULTIPLEXED PHOTOELECTRIC AMPLIFIER SERIES. It is a series range of multiple channel,that have a multiplexed photoelectric amplifiers.Used in a conjunction manner with a relevant number of sets,which has a remote transmitters LT and receivers LR, the MPA series are of 100, 110 and 120. The MPA series are of 3-types;which consists of MPA 21 (2 multiplexed channels); MPA 41 (4 multiplexed channels) and MPA 81 (8 multiplexed channels).In this,the multiplexing function ensures the optical cross talk between channels are prevented.These series offers a choice between individual relays.Each channel,in the MPA operates independently with each other with their own set of remote transmitter and receiver sections.