On Sat, Nov 17, 2007 at 03:34:43PM +0100, Marco Trillo wrote:
> Hi,

> It may not be exactly an ubsa; this message appears multiple times
> when you open a connection to the serial device:
> ubsa0: ubsa_request: STALLED
> but the serial link works.

this is caused by the modem control commands that the device doesn't
understand. I have a new version of ubsa.c (not committed yet) that
should behave better.

> The command is 'ATE0V1E1X1^SYSCFG=2,2,3FFFFFFF,1,2'. This command is
> run just after the AT+CPIN=XXXX command.
> Under the Mac OS X binary, the modem returns a 'OK' response.
> But from my chat(8) script, it returns the following:
> 
> Nov 17 14:00:35 ununoctium chat[1501]: send
> (ATE0V1E1X1^SYSCFG=2,2,3FFFFFFF,1,2^M)
> Nov 17 14:00:36 ununoctium chat[1501]: expect (OK)
> Nov 17 14:00:36 ununoctium chat[1501]: ^M
> Nov 17 14:00:36 ununoctium chat[1501]: ATE0V1E1X1^SYSCFG=2,2,3FFFFFFF,1,2^M^M

Maybe the double ^M ?

E0/V1/E1/X1 are simple commands to control modem behaviour. This
is not really necessary.
^SYSCFG tells the modem what channel to use, i.e. GPRS/EDGE/UMTS/HDSPA
and wether to automatically fall back and forward. The default is
usually ok.

> Anyway I just commented out this command and it seems to work just
> fine... except that just after connecting, it hangs up immediately.

That's ppp disconnecting, you will see more when you enable debugging
on the ppp0 interface.

> Perhaps this is a defective pppd configuration.

Yes and no. You ask for a PPP option that the modem doesn't understand
(you talk PPP to the modem in the card).

> Any ideas?

Try:

connect 'chat -v -f your-connect-script'
nodefaultroute
ipcp-accept-local
ipcp-accept-remote
noipv6
nodetach
noauth
local

as options for pppd. Some providers may require some dummy PAP/CHAP
authentication. t-mobile here does not.

Greetings,
-- 
                                Michael van Elst
Internet: mlelstv@serpens.de
                                "A potential Snark may lurk in every tree."