Send SMS with a Siemens TC35 GSM Modem

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Martin Werthmoeller - 05 Feb 2007 12:28 GMT

Hi all,

I want to send a sms from a monitoring software. As the software fails, I
try to perform this with a terminal program with the apropriate AT
commands.
The output of the TC35 GSM Modem shows no error, but no SMS will be sent.
I checked this with two different sim cards, that have been tested with a
regular cellphone.

Here's the "log" of my terminal session. Could anybody tell me, if there's
an error in my handling?

------------------------------------------------------------------------
AT+CGMI # Print manufacturer
SIEMENS

OK
AT+CGMM # Print model number
TC35i

OK
AT+CGMR # Print version number
REVISION 03.01

OK
AT+CREG? # Is device authorized? (0,1=ja)
+CREG: 0,1

OK
AT+COPS? # Print current GSM network
+COPS: 0,0,"T-Mobile D"

ATDT+49171....... # Test to dial, cellphone rings
BUSY # Drop the call at the cellphone

AT+CMGF=1 # Send SMS as 7bit plaintext message
OK
AT+CMGS="+49171......." # Send SMS to number.
> TEST SMS # SMS text (end with mit CTRL-Z/ESC)
OK

------------------------------------------------------------------------

But no SMS will arrive at the target phone.

Best regards,
Martin Werthmoeller

Signature

Martin Werthmoeller ++ http://www.lw-systems.de/m_werthmoeller

LWsystems - IT-Service and Consulting
http://www.lw-systems.de

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John Henderson - 05 Feb 2007 19:52 GMT

> I want to send a sms from a monitoring software. As the
> software fails, I try to perform this with a terminal program
[quoted text clipped - 5 lines]
> Here's the "log" of my terminal session. Could anybody tell
> me, if there's an error in my handling?

------------------------------------------------------------------------

> AT+CGMI # Print manufacturer
> SIEMENS
[quoted text clipped - 26 lines]
> > CTRL-Z/ESC)
> OK

------------------------------------------------------------------------

> But no SMS will arrive at the target phone.

When you say "(end with mit CTRL-Z/ESC)", what exactly do you
mean? Are you providing both a <ctrl-Z> and an <esc>?

If so, that's your problem. These two terminating characters
are alternatives. <ctrl-Z> (26 ASCII) means send the message,
while <esc> (27 ASCII) means abort the sending. You need to do
one or the other (but not both) to get back to command mode.

You will get a message reference number (+CMGS: nnn) to confirm
the sending, as per this session with a Falcom modem:

ATZ
OK
AT+CMGF=1
OK
AT+CMGS="+6141..."

> Testing 123

+CMGS: 27

OK

John

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Martin Werthmoeller - 07 Feb 2007 04:58 GMT

John Henderson <jhenRemoveThis@talk21.com> meinte:

Hello John,

>>
>> AT+CMGF=1 # Send SMS as 7bit plaintext
[quoted text clipped - 8 lines]
> When you say "(end with mit CTRL-Z/ESC)", what exactly do you
> mean? Are you providing both a <ctrl-Z> and an <esc>?

I tried both variants (CTRL-Z or ESC) with the same behvior.

> If so, that's your problem. These two terminating characters
> are alternatives. <ctrl-Z> (26 ASCII) means send the message,
> while <esc> (27 ASCII) means abort the sending. You need to do
> one or the other (but not both) to get back to command mode.

> You will get a message reference number (+CMGS: nnn) to confirm
> the sending, as per this session with a Falcom modem:
[quoted text clipped - 6 lines]
>> Testing 123
> +CMGS: 27

Ok. Thanks for the info.

Greetings,
Martin Werthmoeller

Reply to this Message

John Henderson - 07 Feb 2007 05:36 GMT

> I tried both variants (CTRL-Z or ESC) with the same behvior.

When aborting the "AT+CMGS" command with <esc>, you should get
an "OK" response back fairly quickly. I'd expect the "send"
variant (<ctrl-Z>) to take longer - about 5 to 8 seconds if
it's actually connecting with the SMSC. About how long does it
take from your <ctrl-Z> to the "OK" response?

Have you tried the "AT+CMGS" command without the quotes around
the destination address? It might make a difference, and I
don't have a Siemens modem to try it on.

Another possible problem area involves the serial wiring. GSM
07.05 (the standard defining the behaviour of "AT+CMGS") says
that (in text-mode) "the DCD [data carrier detect] signal shall
be in ON state while text is entered", and I don't know how a
Siemens modem might behave in the absence of this signal.

You could check that the SMSC address is correct with

AT+CSCA?

and that the text-mode SMS header parameters are set to
acceptable values with

AT+CSMP?

(bearing in mind that numeric values in the result are decimal,
not hexadecimal). If in doubt, you can post the results back
here.

John

Reply to this Message

John Henderson - 07 Feb 2007 19:47 GMT

I wrote:

> Another possible problem area involves the serial wiring. GSM
> 07.05 (the standard defining the behaviour of "AT+CMGS") says
> that (in text-mode) "the DCD [data carrier detect] signal
> shall be in ON state while text is entered", and I don't know
> how a Siemens modem might behave in the absence of this
> signal.

Oops. Just for the record, DCD goes from DCE (modem) to DTE
(computer), so this can't be an issue with a terminal program.

John

Reply to this Message

Martin Werthmoeller - 07 Feb 2007 05:02 GMT

Martin Werthmoeller <mw-usenet@werthmoeller.de> meinte:

I solved the problem.

> AT+CMGF=1 # Send SMS as 7bit plaintext message
> OK
> AT+CMGS="+49171......." # Send SMS to number.
> > TEST SMS # SMS text (end with mit CTRL-Z)
> OK

I could successful sent a message with another SIM card. The card from a
bundled contract (mobile phone + 2 year subscription) will fail, but with
another card (from a prepaid contract in this case) the message could be
sent.

Best regards,
Martin Werthmoeller

Reply to this Message

John Henderson - 07 Feb 2007 05:44 GMT

> I solved the problem.

Only to have it replaced by a different problem... :)

> I could successful sent a message with another SIM card. The
> card from a bundled contract (mobile phone + 2 year
> subscription) will fail, but with another card (from a prepaid
> contract in this case) the message could be sent.

Good luck.

John

Reply to this Message

Andreas Hezel - 08 Feb 2007 12:26 GMT

Martin Werthmoeller schrieb:

> Hi all,
>
[quoted text clipped - 40 lines]
>
> But no SMS will arrive at the target phone.

Hello,
have you set the correct SMSC Adress?

Comment: Request service center address.
***************************************
Subscr 1 Send: AT+CSCA?
Subscr 1 Receive: AT+CSCA?
Subscr 1 Receive: +CSCA: "",129
Subscr 1 Receive:
Subscr 1 Receive: OK
***************************************
Comment: Set service center address. Example: address of O2 Germany.
***************************************
Subscr 1 Send: AT+CSCA=+491760000443
Subscr 1 Receive: AT+CSCA=+491760000443
Subscr 1 Receive: OK

Signature

Andreas Hezel
__________________________________________________________
**********************************************************
Andreas Hezel ---> Mail: AndreasHezel@gmx.de
**********************************************************

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