PPP Chat - optional / non-critical commands

Critcho · 10-22-2006, 12:54 PM

I am running embedded linux on a single-board-controller, version:
BusyBox v0.60.5 (2005.09.26-02:02+0000) Built-in shell (ash)

This device connects to the internet via a GSM modem. We use the chat system to send a pile of commands to the modem. We have however been provided with some older modems that don't support all the commands. Until we get them all replaced by the supplier, is it possible to let PPP Chat continue if a particular command is not supported. I want to be able to add a command that will be sent to the modem, but won't abort on error (i.e. for the older modems):

E.g.

connect "chat -v -t 10 -f /etc/ppp/gprs.chat"

gprs.chat:

Code:

ABORT "NO CARRIER"
ABORT "ERROR"
''
'+\p+\p+\pAT' 'OK'
'ATE0' 'OK'
'ATH' 'OK'
-ABORT "ERROR"
'AT*E2RESET' ''
ABORT "ERROR"
'AT+CSQ' ''
'AT+CGDCONT=1,"IP","MY.SERVER.COM"' 'OK'
'ATD*99***1#' 'CONNECT'

Cheers,
Critcho

petersum · 10-22-2006, 09:57 PM

Probably the easiest way is to use a shell script or even a perl script that will call the chat program at appropriate places, then react according to the expected reply.
There are a number of perl "chat scripts" available that can give you the basic ideas. Google for them!