I wanted to connect my intercom to Homeassistant and there were only some DIY solutions available but nobody made a small PCB that fits into the enclosure of the intercom. So I decided to create one and called it Doorman-S3 because it's heart is an ESP32-S3.

Now it's possible to create several automations to open the front door on specific conditions. Doorbell Ring Patterns are also a great enhancement for automations.

The Doorman S3 Intercom Gateway is a device which lets you connect your TCS or Koch intercom to any home automation system.

There are also some rebranded Niko intercoms which are counterparts of the TCS and Koch ones.

However it's not limited to these intercoms only. With the integrated relay you can easily simulate a button press to trigger the door opener or the light (up to 40V, max 2.5A).

If your intercom is not a TCS or Koch one but operates on a 2-wire bus within the 14-24V range it might be possible to implement other protocols as well.

You could also monitor the voltage level on older intercoms (14-24V) by replacing the tcs_intercom component with a template Binary Sensor combined with ADC and trigger specific actions based on it.