275 PBX interface

The 275 allows an intercom to be connected to an existing PABX analogue telephone switchboard.  By integrating with the phone system, those using the intercom to request access can be answered on existing telephones throughout the building.

Most PABX telephone systems have the ability to transfer calls to another phone, to transfer calls to different departments or even to call groups of phones together.  Calls from the Videx door entry intercom can be placed on hold and transferred to another extension to be dealt with – just like any normal incoming telephone call.

The PABX 275 interface allows more than one person to handle intercom calls and in a commercial property this could conveniently include a receptionist, caretaker and warehouse manager.  In a school, the receptionist, caretaker or teaching staff could field the calls.  A Videx door entry panel can be expanded to include up to 10 separate call buttons to connect with different telephone extensions within the building.

Another advantage of the system is that it can allow after hours visitors calls to be dealt with quickly by automatically transferring the call to another number or mobile. Requests for after hours emergency contact for access can also be dealt with effectively.

Setting up the PABX 275 interface is simply a case of connecting two wires to a free analogue extension port on the Videx intercom.  This will allow it to call a telephone extension or hunt group. When an intercom button is pressed, the relevant extensions will ring and on answer will allow a two way conversation.  The door can be opened by pressing a key on the user’s telephone keypad.

The PABX 275 interfaces are available for use with the popular Videx VX2200 and VX2300 door entry systems and include a two wire version that requires an additional BUS interface.


  • Connects a single button Videx intercom panel to a PBX telephone system
  • A 275-10 interface allows up to 10 call buttons
  • Press button 9 on the telephone keypad to release the door
  • Also compatible with the VX2200 and VX2300 systems (single call button only and requires bus exchange device)
Find a distributor
  • Working voltage: 12Vdc
  • Standby absorption: approx 50mA
  • Max absorption: approx 200mA
  • Working temperature: -10 deg to +50 deg
  • 275 – PBX intercom interface
  • 275-2W – PBX intercom interface (Vx2200 system – requires 2280)
  • 275-10 – 10 Call button expander for 275
  • 275-D – 5 way diode board for 275-10 (4837 and 8837M amplifiers)
  • 275-Z – 5 way diode board for 275-10 (4838 and 136 amplifiers)