for Qwikbus 2-wire technology, voice-controlled door intercom amplifier, voice volume continuously adjustable in both directions, tropicalized loudspeaker, longlife, up to 24 bell and 1 light buttons can be connected, expandable with E32 to a maximum of 184 bell buttons, low-current light buttons and door openers can be connected, for installation in door stations, mailboxes or existing systems, with grid for STR blinds, external dimensions W 142 H 80 D 31mm,
