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Re: Using screen to talk to modems via AT commands
From: |
Amadeusz Sławiński |
Subject: |
Re: Using screen to talk to modems via AT commands |
Date: |
Tue, 18 Apr 2017 10:12:48 +0200 |
On Mon, 17 Apr 2017 08:00:01 -0700
Tim Harvey <address@hidden> wrote:
> Greetings,
>
> I've often asked users I'm helping with modem support on Linux to use
> GNU screen to issue AT
> commands to modems to get their details (ie ATI), however I've noticed
> this doesn't work for me anymore on perhaps newer modems and I'm
> guessing its related to a missing stty setting relative to CRLF.
>
> So the following works from bootup on an MC8790 for example:
> # echo -e "ATI\r\n" > /dev/ttyUSB3
> # cat /dev/ttyUSB3
> ATI
> Manufacturer: Sierra Wireless, Inc.
> Model: MC8790
> Revision: K1_0_2_8AP C:/WS/FW/K1_0_2_8AP/MSM6290/SRC 2008/09/17 14:00:22
> IMEI: 352974021856935
> IMEI SV: 3
> FSN: D661380183210
> 3GPP Release 6
> +GCAP: +CGSM,+DS,+ES
>
>
> OK
> ^C
>
> However if I use 'screen /dev/ttyUSB3 57600,cs8' I find that AT
> commands are never recognized - I get no response from the modem as if
> it didn't catch the right line termination.
>
> Any ideas as to what's going on here and how I could use screen and/or
> stty to resolve it or what the proper stty settings are to avoid this.
>
> Regards,
>
> Tim
Hey,
what version of screen do you use and which distribution?
if it worked before, first thing which would help is narrowing down working/not
working version
( https://ftp.gnu.org/gnu/screen/ )
And then perhaps using git bisect to narrow it down to specific change
(use screen-v4 branch for that
http://git.savannah.gnu.org/cgit/screen.git/log/?h=screen-v4 )
Cheers,
Amadeusz