i cable Nurse Call. Normally open alarm output of ResMed Astral 150 ventilator. Includes 2 pieces uniquely engineered to improve the ruggedness of the vent alarm output.  1) Adapter ME550ASTRAL: 5 pin to 1/8″  phone jack and 2) Alarm cable ME590333N: 1/8″ two circuit phone plug to  1/4″  two circuit right angle phone plug input to headwall jack. This device alarm cable is compatible with the Maguire Device Alarm Input Multiplier, which expands the headwall jack to allow simultaneous monitoring of up to three devices.