CODES: - alt = alternate action, i.e. 1 press is on, one press is off (bi-stable). - mom = momentary action, i.e, connection is made only momentarily then disconnects. - SP = single pole, i.e. 2 points of contact to join 1 wire. DP = double pole, i.e. 4 points of contact to join to 2 wires. mom/alt = momentary switch which then activates the alternate switch. NO = normally open. DT = double throw. ST = single throw.