Inglewood, CA – DoorKing, Inc has introduced a new cellular add-on product for its full line of telephone entry and access control systems. The cellular service provides both voice and programming via ...

Nortek Security & Control today introduced its browser-managed Linear Entry Pro EP-736, EP-436 and EP-402 telephone entry systems Linear designed the Entry Pro “to enable small businesses, gated ...

Camden's TAC IP integrated VOIP and browser based telephone entry and access control system offers exceptional value, a full range of advanced system features and a rugged design for years of ...

The Castlegate Wireless telephone entry system by Corona, Calif.-based Trigon Electronics Inc. is a hands-free system that uses the latest VoIP technology and non-line-of-sight 900MHz broadband RF ...

Lexington, Mass.-based Kantech’s Telephone Entry System is an integrated telephone entry intercom and access control panel is designed for applications including multi-tenant apartment buildings and ...

The circuit provides a simple illustration of a door phone intercom system having a two-way communication using the features of LM386 amplifier. Intercom – short for intercommunication, is an ...