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?