Design Guide for the Gira Door Communication System

The Gira Door Communications System (DCS) is straightforward and with the correct preparation and pre-planning you will have a successful installation.

Cable

The Gira DCS is a digital system so all control signals, audio, video and power run down 2 cores. We recommend using KNX cable throughout the installation as this ensures the best fidelity for your call quality. KNX cable has 2 pairs however as only one is used for the door communication bus, the other is available for supplementary use. If a KNX control system is also being installed, a white sheathed KNX cable can be used for the DCS to make identification of the separate systems easier.

Wiring

All wiring should return to a control unit which will need to be mounted centrally in a cupboard or distribution board. This unit requires a 230V supply and provides connections for a door release. The only connections needed at the external door station(s) and internal home station(s) is the door communication bus.

Star wiring is always recommended which means running a cable from each unit back to the central control unit. 

Connections

If it is an audio only system then each home station can be connected directly to the bus connection on the audio control unit.

For a video system, video distributors are required to combine the signals from each home station before connection to the video control unit. Without these ghosting can occur on the display.

These units have 1 BUS input and 3 BUS outputs. The outputs are connected directly to a video home station, or used to link multiple video distributors together to increase the number of video home stations, as per the above diagram.

Door Release

The audio and video control units both support electric and electromagnetic door locks as they have pulsed and permanent outputs.

For locks that require a short pulse to open, the control units have a 12V output with an adjustable pulse time. This is the more common lock type in residential applications.

For locks that require a constant voltage, the control units have a 12V output that is permanently on. An additional DCS switching actuator is required to interrupt this supply as per the diagram below.

This covers the most common installations of the Gira Door Communication System. For more advanced system or further advice, please get in touch via chat, email or phone.