STR WF 26 Gong apartment intercom, 20370

Apartment intercom WF 26 with gong call, with dynamic microphone loudspeaker for speech communication, gong call and floor call, surface button for voice change and opening function, dimensions: W 85 x H 145 x D 30 mm, installation on switch box or on the surface (the brackets are then removed), circuit diagram, for systems with the power supply unit/amplifier TV20/S + mains transformer and door station LE/B