Hi everyone,

I’m trying to install a Ring Intercom with an old Fermax video intercom (model 3311). The system works, but I’m having a strange issue on the first call.

Setup:

• Intercom: Fermax 3311 (analog video intercom)
• Device: Ring Intercom
• Wiring detected by the Ring app:CT, L, –, V, M, +
• Video works
• Door opening works

Problem:

When someone presses the doorbell:

1. Ring detects the call.
2. I answer on my phone.
3. Video appears for about 1 second.
4. Then the video closes automatically.
5. I still hear the entrance audio from the intercom.
6. I hear a repeating “tic tic tic” sound from the intercom/Ring.

If the person presses the doorbell again immediately:

• everything works perfectly (video + audio + door unlock).

So it seems like:

• first call = unstable
• second call = perfect.

Other notes:

• In Device Health the Ring shows “Intercom Type: Digital FDX”, but the Fermax 3311 is an analog system.
• Wiring has been checked several times.
• The original monitor works perfectly.

Questions:

1. Has anyone successfully used Ring Intercom with Fermax 3311?
2. Could the issue be caused by the call pulse being too short?
3. Would adding a capacitor between CT and ground help stabilize the signal?