Configure another dial-out machine 

How to Configure the Modem and Serial Port (Dial-out Machine).

Test modem connectivity by dialing out to another computer 

cu(1C) and tip(1) man pages. These utilities can help you test if your modem is properly configured. Also, use these utitlities to test if you can establish a connection with another machine.

Get detailed information about the PPP configuration files 

Using PPP Options in Files and on the Command Line.

Begin configuring the dial-in server 

Configuring Devices on the Dial-in Server.