Door intercom with 1 bell button, 2 potential-free switching contacts in metal design. Suitable for surface and flush mounting. Please note additional installation material. An optional power supply is required for the lighting of the nameplate, power supply of the door opener and for the switching contacts (order no. 6101575)! Compatible with AS systems and many PBX systems from other manufacturers (with analog extension) and optimally coordinated (plug'n'play) for AGFEO ES systems! HyperVoice operation only via adaptation.