GSM modem interfacing

hi,i m interfacing gsm modem to my microcontroller.i need to send sms
through it.
i am using AT commands for that.the command to send sms (AT+ CMGS)
terminates with
ctrl-Z.now in my program i hav tried all ways to send  ctrl-Z at end of
my sms.but it takes this as
a character or string only.also i tried with ascii value of ctrl-Z but
of no use.

i am able to see the transmitted commands on hyper-terminal through
serial interface & also on serail window while debugging.
the commands are as follows with 2ms delay between each of them.

AT , AT+CMGF = 1, AT+CMGS = mobile no. , "message to be sent " ctrl-Z /
26 / ^Z


plz suggest some way.suggestions are also invited if you suspect some
other problem .

abhay wrote:
> hi,i m interfacing gsm modem to my microcontroller.i need to send sms
> through it.
> i am using AT commands for that.the command to send sms (AT+ CMGS)
> terminates with
> ctrl-Z.now in my program i hav tried all ways to send  ctrl-Z at end of
> my sms.but it takes this as
> a character or string only.also i tried with ascii value of ctrl-Z but
> of no use.
>
> i am able to see the transmitted commands on hyper-terminal through
> serial interface & also on serail window while debugging.
> the commands are as follows with 2ms delay between each of them.
>
> AT , AT+CMGF = 1, AT+CMGS = mobile no. , "message to be sent " ctrl-Z /
> 26 / ^Z
>
>
> plz suggest some way.suggestions are also invited if you suspect some
> other problem .

Do you send [CR][LF] at the end of each line?
Also, try this before sending messages: AT+CSMP=17,167,0,0[CR][LF]
What answers do you get from modem for each command? Why don't you try
first to introduce commands manually from a Hyperterminal? It would be
of much help.

Adrian

> Do you send [CR][LF] at the end of each line?
yes i m sending  that.

> Also, try this before sending messages: AT+CSMP=17,167,0,0[CR][LF]
> What answers do you get from modem for each command? Why don't you try
> first to introduce commands manually from a Hyperterminal? It would be
> of much help.


i had already tried this on hyperterminal & everything works fine.but i
hav to enter ctrl-z
to indicate my modem that the msg is ready to be sent.now the problem
is how to
 send  ctrl-z via serial interface to modem.

On 31 Aug 2006 21:07:51 -0700, "abhay" <abhaym244@gmail.com> wrote:

>
>> Do you send [CR][LF] at the end of each line?
>yes i m sending  that.
>
>> Also, try this before sending messages: AT+CSMP=17,167,0,0[CR][LF]
>> What answers do you get from modem for each command? Why don't you try
>> first to introduce commands manually from a Hyperterminal? It would be
>> of much help.
>
>
>i had already tried this on hyperterminal & everything works fine.but i
>hav to enter ctrl-z
>to indicate my modem that the msg is ready to be sent.now the problem
>is how to
> send  ctrl-z via serial interface to modem.
___
You might try Googling for the ASCII codes.  The first 32 are
non-printing characters and were used to control teletype machines.
One of these might work to send the message to the modem(all decimal):
3 EOX, End of text
4 EOT, End of transmission
23 ETB, End of transmission block

I seem to remember that ctrl-Z was also used as an end-of-file
character in BASIC
___
Catapultam habeo. Nisi pecuniam omnem mihi dabris, ad caput tuum saxum immane mittam.--
I have a catapult. Give me all of your money, or I will fling an enormous rock at your head. 

abhay wrote:
> now the problem
> is how to
>  send  ctrl-z via serial interface to modem.

Send a ctrl-z from hyperterminal and look with an oscilloscope a the
character generated.
You will find that ctrl-z is 0x1A

Adrian