Aircraft communications apparatus
Automatic intercom system for buildings
Call controlling apparatus and method used for an order-wire...
Collective house interphone system and method therefore
Communication controlling apparatus for a single-line telephone
Communication system for use in a mine
Control device for a lift
Door intercom device
Door security system
Entrance intercom system
Integrated communications control device for a small office conf
Integrated telephone intercommunication and alarm electronic con
Intercom system
Intercom with transducer enclosure to attenuate resonant frequen
Intercommunication system
Internal telephone intercom system
Interphone system
Method and apparatus for communication with a gate entry...
Method and apparatus for installing telephone intercom--voice me
Method and apparatus for installing telephone intercom-voice mes