It USED TO BE that to run Dialer you needed the expectk program, but no longer (now Dialer runs on basic tcl/tk).
Dialer expects a Hayes-compatible modem (like nearly all modems sold these days).
The status of the connection-attempt is presented in a dialog box on the screen. You see what number is being dialed, what speed you connect at, and the reason for any failure to connect.
All settings are configurable in the Settings window (click the "Settings" button). You need to set your modem port and port speed, and the phone number (or list of numbers, or a repeat-dialing script) you want to dial. Optionally, you can set one or two modem init strings and a unix command to execute when successfully connected (like pppd). You also can construct a login script. This is all done on-line and is self-documenting (use the "Help" menu in the Settings window). You save your settings information in a file in the usual way (with "Save" in the pull-down "File" menu), and you can have different settings stored in different files.
At startup you can indicate your settings file and also a command to run right away (the command "Dial" starts the dialing just like hitting the "Dial" button. So, to start dialing right away, you issue a unix command like this:
Dialer /home/markcrim/.DialSettings Dial
I use Dialer on my Linux home computer, and I do not have access to any other unix platforms with dial-out modems, so I cannot be sure this will work on other platforms. But I have heard good things from people on various Unix platforms, so it's worth a try.