(916) 672-2660 An intercom also known as an intercommunication device, doorphone or talkback is a standalone voice communications system. These systems are used in a buildings and/or a small collection of buildings. Each intercom functions independently of the nation’s public telephone network. These talkback systems are permanently mounted in vehicles and buildings. Intercommunication devices can incorporate walkie-talkies, telephones, public address loudspeaker systems, and other intercom systems. High-end intercom systems can incorporate the control of devices like door latches and single lights.