Looking for a wireless intercom system with local power supply

Or you use e.g. a Doorbird D2103V (WLAN).

Thanks for the Doorbird tip - that's like using a sledgehammer to crack a nut for me - I definitely don't need a camera and access chip. WLAN connectivity, on the other hand, is appealing.

Then please test the connection first at 35 meters and with walls in between. In the 2.4 GHz network, there are many interferences from other wireless networks. Therefore, I did not mention it either. Especially since doorbell and door opener would not go into the cloud for me...

Then please test the connection first at 35 meters and with walls in between. There are many interferences in the 2.4 GHz network caused by other wireless networks. That's why I didn't mention it. Especially since I wouldn't want the doorbell and door opener to go into the cloud...

I mean you can also operate the Doorbird without the internet, but some functions cannot be used.

It's just a wall made of wood. I prefer a different material than you, Rick. By the way, if you want to see beautiful concrete, I recommend a visit to the Langen Foundation. The Japanese architect Ando is famous for silky concrete. To my knowledge, it is his only building in Europe. It is located near Neuss.

The second best solution would be to just run power there,

If that is acceptable to you, I even have a proposed solution. Look for TP Link, powerline adapters, etc. These send the network signal over the electrical wiring. So you plug something into the socket at one end, and you can also connect a LAN cable to it. At the other end where the power line ends, the same plug goes into the socket and you can tap the signal again via LAN cable. So you have power AND a network signal. The adapters are also available with WiFi, but I find LAN better. Aside from the fact that WiFi outdoors can be attacked even more easily than in your apartment, the data throughput with LAN is simply much higher. This also makes video transmission easier (e.g., doorbell with camera). But even without a camera, I would pay attention to a high data throughput for voice quality. Maybe you have already experienced how well IP telephony works with a poor data connection (you can test with Skype). I advise against the idea of intercepting the WiFi signal from the house over 35 meters. Try testing with your phone how good the signal and data throughput are when you are 35 meters away from the house.... That is not a stable solution.