Dialup is accomplished through the pon and poff commands in Debian - in the special case of an analog connection. Digitally connections (ISDN) work different.
The syntax is as follows:
- pon provider_name
- poff provider_name
The details for a given provider (telephone number, modem, etc.) are configured using the pppconfig command.
Note: Your modem must be properly set up before you can use it for dialup. You may need to configure your kernel and/or the serial port connected to the modem.
pon and poff also control PPPoE links, which instead of dialing through a modem tend to either be carried over Cable or DSL (which happens to use the phoneline, but lets normal voice/modem signals by unmolested). This is often carried into your computer through Ethernet.
NetworkManager (in both Gnome and KDE) let you graphically control Dial-up connection.
With pppconfig(8) you can have "dial on demand", which means the modem will dial whenever you want to surf a page or send data to the Internet. In this case, you need to have 'pon' run before.
To automatically have pon run when the computer boots up, see /usr/share/doc/ppp/README.Debian.gz and interfaces(5).