What the existing connection tells
The outdoor post, indoor post and electric door opener can each have different power requirements. An old bell transformer is designed for a simple gong and not automatically for all new parts.
advice
Video phone: check power supply and call transformer
A video phone that sometimes restarts or does not give a call signal regularly has a power issue, but that must be investigated by component by component.
The technical choice
First, identify which transformer powers which component and which specifications are listed on the equipment. Pay attention to the behavior when ringing and opening the bell; at that exact moment, the load may change.
What you let me arrange
Choose a suitable power supply or separation when existing voltage, power or wiring does not match. Do not combine power supplies on a case-by-case basis and leave unused old wires safely terminated.
Delivery to the door
Test multiple call moments in a row, speaking connection and door opening with normal door bell load. Then check whether the outside post does not restart and the inside post remains reachable.
Frequently asked questions
Can an old doorbell transformer power a video phone?
Sometimes, but only if tension and ability are demonstrably appropriate.
Why does the intercom work but the door doesn't open?
The door opener may have its own power or relay request that is separate from the video image.