There is a device I am doing testing on that can either use dial-up as a backup connection or if the location does not have broadband it can use dialup as the primary connection. It has been interesting doing so much dialup testing recently since it has been almost 10 years since I have done much with dial-up. One of the ways to test dialing out from Linux is to use minicom which will allow you to communicate with the modem installed on your computer. So minicom will setup the connection to the modem and then AT commands can be used to dial the number of your dialup provider. Below we describe how to configure minicom and then a brief list of AT commands that can be used.
There are numerous applications that will allow you to connect to the serial port of a router, switch, load balancer, or other network device. I found the easiest application to use is the trusty old minicom. Minicom is very plain and has an easy configuration which is why I prefer it.
The man page calls minicom a “friendly serial communicator program”.