Intermittent crackling, low volume & missing chime segments when tapping BUS+ / BUS– in parallel

[ProOZx]

Hi,
First, @Mat931 thanks a lot for sharing this project.
I have connected my Busch-Jaeger 83210 Indoor Station with the ESP and it flawlessly receives the door bell events and the door opener also works fine.

Since adding the ESP32-doorbell-bus-interface in parallel to my Busch-Jaeger 83210 indoor station, I’m seeing three problems during intercom calls and chimes:

1. Intermittent crackling noise
-> Starts as soon as the “phone” (talk) circuit closes—lasting for the entire conversation.
2. Significant volume reduction
-> Both outdoor and indoor stations are much quieter. Increasing the indoor-station volume setting helps only slightly but the counter part on the outdoor station can only hardly understand whats spoken.
3. Chime truncation
-> Occasionally only the first tone of the doorbell ring plays, then it cuts off.

I tried to connect everything as I've read it in the wiki and the issues, for example in this issue.

I've attached a drawing of how i did it, please forgive my poor drawing skills.

Do you have any hints on how I could improve wiring or configuration to get rid of these issues?

[Mat931]

Hi,

1. Intermittent crackling noise
Some crackling noises are normal — they are caused by electrical noise on the bus. For example, when a message for the door opener is sent or when the ESP uses more power to send something over Wifi that can interfere with the audio and video transmission. If your interference problems are stronger, that could be a sign of a probem with your PCB — for example a missing capacitor. Your connections look good to me. It may help to make the wires between your Wago terminals and the PCB as short as possible to reduce interference.

2. Significant volume reduction
I don't know if it's possible to fix the volume reduction you described.

3. Chime truncation
The chime truncation can be caused by someone ringing your doorbell and then someone else's right afterwards. Your doorbell stops when another one starts ringing.

I hope this helps!