Configuration:

1. Install pppd
2. Create /etc/ppp/peers/s45_indigo something like the following:

   # These are the options to dial out to your default service provider.
   # Please customize them correctly. Only the "provider" file will be
   # handled by poff and pon (unless with extra command line arguments).
   
   # You usually need this if there is no PAP authentication
   noauth
   
   # I've added the export commands to set up $DNS1 & $DNS2 with indigo DNS servers
   # The chat script (be sure to edit that file, too!)
   connect "export DNS1=194.125.133.10; export DNS2=194.125.133.11; /usr/sbin/chat -v -f /etc/chatscripts/s45_indigo"
   
   # Set up routing to go through this PPP link
   defaultroute
   
   # Default modem (you better replace this with /dev/ttySx!)
   /dev/ttyS0
   
   # Speed
   115200
   
   # Keep modem up even if connection fails
   persist
   
   # Tell pppd to set up DNS servers set above
   usepeerdns
   
   # Username/password to use from /etc/ppp/chap-secrets
   user "username1"
   
   

3. Create /etc/chatscripts/s45_indigo something like the following:

   ABORT "BUSY"
   ABORT "NO CARRIER"
   ABORT "ERROR"
   ABORT "NO ANSWER"
   ABORT "NO DIALTONE"
   ABORT "Username/Password Incorrect"
   REPORT "CARRIER"
   REPORT "CONNECT"
   "" "AT"
   # Put your ISP Phone Number after ATDT below
   OK "ATDT1891110110"
   CONNECT '\d\c'
   

4. Add a line to /etc/ppp/chap-secrets something like the following:

   username1	"*"	"password1"
   

5. Type the following:

   gavin@linux gavin> pon s45_indigo
   

   or if pon is not a known command

   gavin@linux gavin> pppd call s45_gprs
   

   You should then see the phone screen show it's dialling the phone number and after a few seconds a connection should be established. ifconfig will show a ppp connection once it's setup.
   
   
6. To disconnect type the following:

   gavin@linux gavin> poff s45_indigo
   

   or

   gavin@linux gavin> killall pppd