MODEMs and Asynchronous Dial-up

Believe it or not, there are good reasons to use MODEMs on POTS lines to this day. One may want to have a MODEM connected to a router for out-of-band communications in case of disaster recovery. A Typical MODEM Connection [Host]–[MODEM]—-[Telco Switch]—-[Telco Switch]—-[MODEM]–[Host] MODEM Signaling – Control Pin 2 = Transmit Data Pin 3 = [...]