Send SMS with a Siemens TC35 GSM Modem
Martin Werthmoeller
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
--
Martin Werthmoeller ++ http://www.lw-systems.de/m_werthmoeller
LWsystems - IT-Service and Consulting
http://www.lw-systems.de
John Henderson
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
Martin Werthmoeller
Hello John,
> Martin Werthmoeller wrote:
>
>>
>> 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.
>
> 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:
>
> ATZ
> OK
> AT+CMGF=1
> OK
> AT+CMGS="+6141..."
>> Testing 123
> +CMGS: 27
>
Ok. Thanks for the info.
Greetings,
Martin Werthmoeller
Martin Werthmoeller
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
John Henderson
> 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
John Henderson
> 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
John Henderson
> 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
Andreas Hezel
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
--
Andreas Hezel
__________________________________________________________
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Andreas Hezel ---> Mail: Andrea...@gmx.de
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