Strange GPRS modem problem (wavecom fastrack supreme)

#1 (**permalink**) April 11th, 2008, 11:17 PM

Hi all.

I'm trying to use a Wavecom fasttrak supreme to make a gprs connection,
and I'm getting the repeatable problem that connection attempts
alternatively succeed or fail - if this one works, then next one will
fail, and so on.

I'm power cycling the modem between attempts, and using exactly the same
setup commands each time, I don't understand why the behaviour should
alternate...

The problem is in the AT+WIPBR=4,6,0 command, and the error it reports
is +CMS ERROR: 811, which appears to refer to the SIM's PIN code, but
this doesn't make sense - the SIM doesn't have the PIN enabled, and why
would this change alternately anyway?

Example logs:

Power-up modem

First we make sure the SIM is registered on the network
Tx[ AT+CREG?]
Rx[ +CREG: 0,1]
Rx[ ]
Rx[ OK]

It is, so setup the IP

Tx[ AT+CMEE=1]
Rx[ OK]
Tx[ AT+WIPCFG=1]
Rx[ OK]
Tx[ AT+WIPBR=1,6]
Rx[ OK]
Tx[ AT+WIPBR=2,6,11,"internet"]
Rx[ OK]
Tx[ AT+WIPBR=2,6,0,"user"]
Rx[ OK]
Tx[ AT+WIPBR=2,6,1,"pass"]
Rx[ OK]

Here's the problematic command, this time it'll work

Tx[ AT+WIPBR=4,6,0]
Rx[ OK]

And then we go on to make the connection, etc

Tx[ AT+WIPCREATE=2,1,"82.69.59.37",9191]
Rx[ OK]
Rx[ +WIPREADY: 2,1]
Tx[ AT+WIPCLOSE=2,1]
Rx[ OK]

So that all worked. But now if I power the modem down and back up again
the next time it will fail...

Power modem down, and back up again

First we make sure the SIM is registered on the network
Tx[ AT+CREG?]
Rx[ +CREG: 0,1]
Rx[ ]
Rx[ OK]

It is, so setup the IP

Tx[ AT+CMEE=1]
Rx[ OK]
Tx[ AT+WIPCFG=1]
Rx[ OK]
Tx[ AT+WIPBR=1,6]
Rx[ OK]
Tx[ AT+WIPBR=2,6,11,"internet"]
Rx[ OK]
Tx[ AT+WIPBR=2,6,0,"user"]
Rx[ OK]
Tx[ AT+WIPBR=2,6,1,"pass"]
Rx[ OK]

Here's the problematic command, this time it'll fail

Tx[ AT+WIPBR=4,6,0]
Rx[ +CME ERROR: 811]

And I can repeat that forever without success

Tx[ AT+WIPBR=4,6,0]
Rx[ +CME ERROR: 811]
Tx[ AT+WIPBR=4,6,0]
Rx[ +CME ERROR: 811]

etc

If I now power cycle the modem again the next time it will work. It then
fails. It then works. And so on...

I have tried sending close commands ( AT+WIPBR=5,6 AT+WIPBR=0,6 ) before
I power the modem down, but it doesn't make any difference.

Anyone out there got any bright ideas?

Cheers, Simon Brattel

#2 (**permalink**) April 19th, 2008, 10:50 PM

> I'm trying to use a Wavecom fasttrak supreme to make a gprs connection,
> and I'm getting the repeatable problem that connection attempts
> alternatively succeed or fail - if this one works, then next one will
> fail, and so on.
>
> I'm power cycling the modem between attempts, and using exactly the same
> setup commands each time, I don't understand why the behaviour should
> alternate...

And the answer was... God knows, never solved it. But probably it was
related to the fact that like most cellular modems it's a complete pile
of shite.

PIGO - Programmers Involved; Garbage Out.