Audio speaker unit for Simplebus system, complete with terminal block and digital audio management system with Eco-cancelling, watertight loudspeaker and electrets microphone, loudspeaker volume can be adjusted from the front. Complete with microprocessor and DIP SWITCH with 8 positions for programming user calls. 33Vdc power supply via special power supply unit Art. 1595. On-board electronic lock-release function (3A), plus a 10A relay. For use in modules Art. 33400, 33401 and 33402. Dimensions: 102x55x38 mm. Compatible with all Simplebus 2 functions and products. It allows call addressing for up to 120000 users. Timed lock-release inputs and door open indication.