My apartment building has an old hard-wired Enterphone intercom to buzz visitors in. This poses a slight annoyance since the dependency of the phone line in conjunction with a conventional corded telephone means I have to walk to the phone in order to answer the intercom.
Given the low rate of visitors and the small size of my apartment, in retrospect, this isn’t really a big deal. Most normal people would just buy a cheap cordless phone and call it a day.
But that only helps if I’m in the apartment. What if I wanted to be able to buzz myself in if I somehow got locked out?