Hi Mike,

>
> It looks like AT&C0 is correctly being issued, from the logs here:
>
> ofonod[1398]: plugins/huawei.c:sysinfo_enable_cb() 255 -> 1
> ofonod[1398]: Modem: > AT&C0\r
> ofonod[1398]: PCUI: > AT&C0\r
> ofonod[1398]: PCUI: < \r\nOK\r\n
>
> I'm using a Huawei e173:
> ofonod[2008]: Modem: < ATE0 +CMEE=1\r\r\nOK\r\n
> ofonod[2008]: PCUI: < \r\nManufacturer: huawei\r\nModel:
> E173L\r\nRevision: 21.106.04.00.982\r\nIMEI: 868387000063372\r\n+GCAP:
> +CGSM,+DS,+ES\r\n\r\nOK\r\n

Yes, certain models of Huawei modems are the main culprits.  There have 
been a few suggestions on how to solve this, but it is quite nasty & 
requires re-opening the AT modem port.  Nobody had the itch to fix it 
properly.

>
> Is there any way I can see if the modem is closing the command port?
>

strace, or use g_at_chat_set_disconnect_function() and see if that gets 
called.

Regards,
-Denis