Apparently our building elevators have a communication system that can be dialed from outside, and since they are, well, elevators, they automatically pick up the call. Now some spammers have the elevator number and the elevators being robodialed with offers for timeshare vacations that can't be disconnected by the riders.
Taking the stairs, thanks.
@BrokenBiscuit I guess it needs to be connected somehow so you can call the fire department if you get stuck, but why in the hell should an elevator be able to receive calls from non-government numbers I'll never know
@fobo @BrokenBiscuit The fundamental answer is basically that the phone companies just *don't do* special-purpose telephone numbers, on a technical level. "Private" or "specialized" lines actually have a public number somewhere that isn't published to anything. There's scads of tales of people mis-dialing and getting like... A USAF command center or some such.
The only way you genuinely get a phone that nobody unauthorized can right is to run your very own cables to everyone authorized.
@fobo