The ADT-CTF is a technical data sheet designed to interface an intercom with a 12 V electric lock output (typical opening command) to the START input of an automation control unit (gate, door, shutter) that requires a dry contact (i.e. relays with no residual potential).
Unlike a simple galvanic isolator, this module uses relays with dry contacts to ensure that any charge, current return or disturbance on the intercom line does not affect the electronics of the control panel.
It is particularly suitable in cases where:

• The intercom line is very long and prone to disturbances or eddy currents.

• The output of the intercom supplies voltage (12 V) and not a potential-free contact.

• Do not want any overvoltages or returns to damage the START input of the control panel.

Operation
When the intercom activates the 12 V electric lock, the ADT-CTF card detects this voltage and powers an internal relay that switches the NO/COM contact (with no potential applied) towards the START input of the control panel. In this way, the control panel "sees" the control as a simple free contact, without being subjected to extraneous voltages or unwanted currents.
The relay with dry contacts behaves like a mechanical switch: it does not transfer voltage from the intercom to the control panel, but only the status of the control.

Main features

• Input: 12 V intercom output (typically electric lock)

• Output: Relay with dry contacts (NO/COM)

• Protection against eddy currents and line disturbances

• Ideal for installations with extended intercom line

• Easily integrated into junction box or electrical panel

• Compatible with control panels that require dry contact on the START function

Typical Applications

• Intercom or video intercom connection to the automation control unit without directly using the intercom voltage

• Conversion of a 12 V control into a dry contact for automation

• Environments with strong disturbances or long intercom cable runs (apartment buildings, residences, industrial plants)