Can I use Doorman?

If your TCS, Koch or Scantron indoor station has a, b, and P labeled screw terminals and operates on 24V DC, it's likely compatible.

Some rebranded Niko and older Jung indoor stations, which are counterparts to the TCS and Koch models, may also be compatible.

READ - BEFORE YOU ORDER

Since this product is the result of reverse engineering, there is no guarantee that your indoor station will work without testing it yourself.

1. Check the wiring and measure the voltage before ordering a Doorman.

2. There is no guarantee that Doorman will work with your intercom due to the unique wiring in each building.

3. Other devices on the P-line (e.g., your neighbors' equipment) may draw too much current, potentially affecting Doorman's performance.

Understand these risks before purchasing. If you have any questions, please contact me, and I will be happy to help!

Wiring

2-Wire Mode:
If your indoor station is connected in 2-wire mode and you don't have a separate 24V P-line, use either the BUS PWR jumper (starting with rev. 1.5), an external power supply via USB-C or the P (+5V to +30V DC) and b (Ground) screw terminals.

3-Wire Mode:
If connected in 3-wire mode, you should be able to use the P-line to power your Doorman in most cases.

TIP

In some installations, the a and b wires are twisted, but this is handled by Doorman's integrated bridge rectifier. Consider this when checking the voltage levels on the a, b, and P lines.

Indoor Station Screw Terminal Explanation

• a: Typically the Bus line (+24V)
• b: Typically Ground
• P: The +24V line in 3-wire mode or the apartment doorbell button in 2-wire mode

DANGER

AVOID USING THE +24V P-LINE AND USB-C PORT AT THE SAME TIME.
NEVER CONNECT A POWER SOURCE TO THE TC:BUS TERMINALS - DOING SO CAN CAUSE SEVERE DAMAGE.

Check the Power Supply

Use a multimeter to check the DC voltage.
Measure the polarity first since the a and b lines can be twisted.

Expected Voltage

• Between a and b: ~ 24.0V
• Between P and b: ~ 23.2V

WARNING

The intercom power supply must have a minimum output current of 60mA for stable operation.

If other devices using the P-line draw too much current, it may not be sufficient to power Doorman.

Use an external power supply (USB-C or screw terminal) if your intercom's power supply provides less than 60mA or if you notice unstable operation.

Known Issues

Indoor stations with a TTC1-B-1 connector module cause issues because the a and P lines are connected. Starting with revision 1.5 this issue is addressed with a new power supply option which will only produce a subtle, yet noticeable hissing sound on the speaker using the mentioned module.

Problem for revisions older than 1.5

A loud beeping noise occurs whenever someone is talking.

Verified Hardware

Check out the supported models and settings.
Models with available settings are guaranteed to be compatible. If your model isn't listed, please open an issue to verify its compatibility.