[En-Nut-Discussion] Pausing PPP to interogate a GPRS modem

[Brett Abbott]

Mike,  Thanks for your reply - very helpful.  

Further on the interrogation of a GPRS modem.  Be aware that most modems allow a more elegant (and speedy) means of executing commands whilst in a call (both PPP and data call).  (ie. to check Signal Strength, issue AT commands, perhaps change pin numbers etc whilst still in a session).

There is an AT config command which allows you to switch between command (issue AT commands) and Data Mode (assuming you are in a PPP session for GPRS or data call for GSM) using the DTR signal line.  When this mode is set prior to the connection, you can raise/lower DTR to go between modes - This effectively avoids the 1 second delay whilst the +++ escape sequence takes hold and gives some certainty to the call mode - always a bit dodgy when you have multiple reasons why +++ wont work.

Ive tested this method (ie. pausing PPP session to execute commands) on several modems with success from a PC, however not from Ethernut yet but expect no issues.

Cheers and Thanks
Brett


Message: 5
From: "Mike Cornelius" <mikec at call-direct.com.au>
To: <en-nut-discussion at egnite.de>
Subject: RE: [En-Nut-Discussion] PPP Retrying when no PPP/GPRS is available
Date: Wed, 24 Sep 2003 11:06:51 +1000
Organization: CDCS
Reply-To: en-nut-discussion at egnite.de

Hi Brett,

Second things first, I've not tried interrupting the PPP session whilst
it's going and then going back.
I assume you're thinking something like:

<>PPP[]

>>+++
>>AT+CSQ?
>
<+CSQ: ??,??

>>ATO
>
<>PPP[]
But it's certainly an interesting idea and if I get a chance I give it a
whirl and let you know what I find.


-- 
-----------------------------------------------------------------
Brett Abbott, Managing Director, Digital Telemetry Limited
Email: Brett.Abbott at digital-telemetry.com
PO Box 24 036 Manners Street, Wellington, New Zealand
Phone +64 (4) 5666-860  Mobile +64 (21) 656-144
------------------- Commercial in confidence --------------------

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.egnite.de/pipermail/en-nut-discussion/attachments/20030924/6a9d69e8/attachment.html>