We removed the old doorbell with a built-in camera. The client didn't want to pay monthly for using the old intercom. So, we installed a professional video intercom system where there's no need for monthly app subscriptions. The system consists of the door locking itself with a built-in video camera. When the doorbell button is pressed, it sends a signal to a monitor inside the house. The video signal is also sent to the client's mobile phone, allowing them to answer calls from anywhere in the world. The challenge was that the house renovation was already completed, but we managed.
Additionally, we removed the old surveillance system and installed a new professional surveillance system consisting of 7 surveillance cameras and a video recorder. We placed the server storing all recordings in the storage room. The client doesn't need to pay monthly for cloud services, etc. They own their information.