A drive mechanism using shape memory alloy which, even if used repeatedly, is free from the weakening or loss of the shape memorized by the driving member of the shape memory alloy and capable of driving driven members accurately for a long period of time, and an apparatus using this drive mechanism. The apply port is sealingly fluidly isolated from the supply port, the delivery port, and the exhaust port. The systems and methods provide advantages because a communication network can be protected, at least in-part, against active equipment failure, passive equipment failure, andor equipped for non-intrusive expansion of the network.