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 unit is required for the illumination of the nameplate, power supply for the door opener and for the switching contacts (order no. 6101575)! Compatible with AS systems as well as many telecommunications systems from other manufacturers (with analog extension) and optimally coordinated (plug'n'play) for AGFEO ES systems! HyperVoice operation only via adaptation.