Urmet Intercom Set 1122/31 2-Wire Door Intercom Set, Intercom System, Complete Set (Ringing, Talking, Listening, Opening Door) Bell Mute Switch, Turn Your Bell with 2 Wires into a Complete Intercom : Amazon.de:
Suoneria esterna su Urmet 1122/601 - Citofoni, videocitofoni e intercomunicanti - PLC Forum