SMS Confirmation

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Guy Cohen - 26 Feb 2004 10:02 GMT

Hi all.

I develop an application that uses a GSM module to send SMS to a user list.
Interface = AT Commands.

When I sent the SMS I got:
CMGS: 225

I used CNMI=0,1,0,1,0 so I got a confirmation:
CDS: 32,2,"04/02/26,11:46:26+4","04/02/26,11:46:32+4",0

How can I be sure that the confirmation belongs to the SMS I sent (225)

TIA
Guy

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John Henderson - 29 Feb 2004 06:31 GMT

> I develop an application that uses a GSM module to send SMS to
> a user list.
[quoted text clipped - 8 lines]
> How can I be sure that the confirmation belongs to the SMS I
> sent (225)

According to GSM 07.05, the format of the "CDS: " response is:

+CDS: <fo>,<mr>,[<ra>],[<tora>],<scts>,<dt>,<st>

(see section 3.4.1 for details).

In your example, <fo> (first octet) is 32 (status report
indication), and <mr> (message reference) is 2 (presumably
corresponding to a "CMGS: 2" message sent earlier). Fairly
obviously, the next two values are <scts> (service centre time
stamp) and <dt> (message discharge time stamp). In these
timestamps, the "+4" means GMT + 1 hour.

It's not clear to me how closely your message confirmation
(reference 2) is supposed to match your sent message (reference
225), in you examples. If you were expecting only a confirmation
of message 225, then I can't explain the <mr> = 2.

John

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