In the US, the device you enter the numbers on is called a keypad. The entire setup is an intercom system. It is almost always built into the wall of the building or attached to it. It doesn't hang on the door. When I lived in San Francisco, a visitor would use a keypad to input the code beside my name, my phone would ring, and I would talk to the person through my phone. They could hear me through the intercom, which is a speaker at the front door. If I wanted to let the person in, I pressed 0 on my phone, a buzzer would ring downstairs, and the door downstairs would open. In my condo in San Diego, the situation was similar, except the front gate also had a camera so I could see the person on a video screen in my apartment. If I wanted to let them in, I would talk to them on the phone, look at the video screen, and then "buzz them in" by pressing 0 on my phone. They could hear and speak to me through the intercom at the front door. In my apartment in Philadelphia, if someone wanted to see me, they would use the keypad to press the code beside my name and a buzzer would ring in my apartment. I could talk to them through the intercom in my apartment and they would answer through the intercom at the front door. I could then press a button on the intercom box, the buzzer would ring, and the door would open. No phone needed. My current apartment is a high-rise, and it has a setup similar to the first two, except no camera. However, like the first two, it requires a land-line phone and I only have a cell phone so I can't use it. If someone wants to see me, they must call me on my cell phone and I go downstairs and let them in. So as you can see, there are several different setups. They all involve some combination of a keypad, phone, intercom, and buzzer. They look like this: https://bit.ly/3glIv9M OR this: https://flyinglocksmiths.com/services/intercoms/butterflymx/

Intercom ... for example: https://www.intercomsonline.com/Apartment-Intercoms-s/89.htm

The word you want is "Intercom." Также эта система используется в офисах. Для секретарей поговорить с боссами в их офисе.