Re: some problem

[James Cameron <quozl@laptop.org>]

On Wed, Mar 03, 2010 at 11:41:15PM +0900, Murali K. Vemuri wrote:
> Jan  1 00:02:37 (none) local2.info chat[109]: send (AT^M)
> Jan  1 00:02:37 (none) local2.info chat[109]: send (AT
> +CGDCONT=1,"ip","web.sktelecom.com",,,^M)
> Jan  1 00:02:38 (none) local2.info chat[109]: send (ATDT*98#^M)
> Jan  1 00:02:38 (none) local2.info chat[109]: expect (CONNECT)
> Jan  1 00:03:23 (none) local2.info chat[109]: alarm

There's no evidence in that chat log that you are receiving anything
back from the modem.  You should receive OK in response to AT and
AT+CGDCONT.  Can you confirm that with a manual connection between
keyboard and modem?

A common cause of this is modems that provide two USB endpoints; one for
firmware update, one for communications.  The firmware update endpoint
may not respond.  For one modem, I fixed this by using the next device
name; /dev/ttyUSB1 instead of /dev/ttyUSB0.

Otherwise, the sequence looks acceptable.  For a sequence that I've
tested with a different modem, but which works with every other modem
I've tried, see:

http://quozl.linux.org.au/darcs/eee-bpw/etc/chatscripts/bpw

In this particular instance, an additional check AT+CGATT? is done to
verify that the modem has attached to the network ... before attempting
a connection.

-- 
James Cameron
http://quozl.linux.org.au/