that you will be dialling. For example, suppose the file is called
/etc/ppp/peers/isp. This file would contain something like this:
-cua0 # modem is connected to /dev/cua0
+ttyS0 # modem is connected to /dev/ttyS0
38400 # run the serial port at 38400 baud
crtscts # use hardware flow control
noauth # don't require the ISP to authenticate itself