Additional digits to GSM calling number

Hi there!

I hope this is the right place to ask - if not, please tell me which
usenet group I should use. Also, I don't really know how to ask this so
please bear with me. I am a newbie at this field... :)

I am planning on using a GSM module (Siemens TC65, but that shouldn't
matter). The module should do something when someone calls it. But the
caller should also have an option to enter a digit after the number and
(with that) pass a parameter to the program.

So instead of just entering:
+451321324   // this is the phone number
the caller enters:
+4513213241
or:
+4513213242

The module should be able to read "1" or "2", act appropriately, all
without answering the call.

Is this possible?

I was told ISDN modems were able to "read" the additional numbers
without answering the call.

Thank you for any help, hints,... 

Best,

Anze

> I am planning on using a GSM module (Siemens TC65, but that shouldn't
> matter). The module should do something when someone calls it. But the

Of course it would matter. The module would need to have firmware
support for this feature, if it was even possible.

> the caller enters:
> +4513213241
> or:
> +4513213242
>
> The module should be able to read "1" or "2", act appropriately, all
> without answering the call.

This would be something you need to discuss with your carrier. I do not
think it is directly possible. You could, however, have multiple phone
numbers assigned to the module by the carrier and use the equivalent of
distinctive ring to determine which one has been called. The module
would need to support this.

You could also have multiple numbers _forwarded_ to the module, as the
GSM protocol does include "forwarded from..." info. Of course, the
module would need to support this.

Hi,
>
> So instead of just entering:
> +451321324   // this is the phone number
> the caller enters:
> +4513213241
> or:
> +4513213242
>
> The module should be able to read "1" or "2", act appropriately, all
> without answering the call.
>
> Is this possible?
>

I doubt it.
Dialing in terms of GMS (and ISDN two) is done by signalling and I am not 
even sure that GSM mandates something like early dialing where digits are 
passed one by one and feetback is given on each entry.
Instead, the number is dialed as a block and my guess is that extra numbers 
are either truncated at this point or simply lead to an error.
You'll have to use DTMF commands to do what you need unless you arrange with 
your provider.
/Roland

> > Is this possible?
> I doubt it.

Thank you both for your answers! 

Best,

Anze