Re: 300baud FSK over GSM

From: Denis Gleeson (dgleeson-2_at_utvinternet.com)
Date: 09/30/04 

Date: 30 Sep 2004 04:15:28 -0700

Hello everybody

Thanks everybody for your excellent input. Its given me lots of room
for thought.

Slight mistake in my description of the problem. Let me start again.

What I said was;
 
"Essentially the requirement comes from the fact that the equipment
at the far end can only communicate at 300baud FSK over the PSTN
network.
Our end will work with GSM and needs to communicate at the 300 baud
FSK."

What I should have said was;

Essentially the requirement comes from the fact that the equipment
at the far end can only communicate at 300baud FSK over the PSTN
network.
We are connecting a board to this equipment which will have a GSM
module (modem) on it.
Our end will be a standard PC with a PC modem(connected to PSTN)."

I had hoped(and I doubt my wisdom on this now) that we could place the
call with
the GSM modem and simply connect the PSTN output of the equipment to
the GSM
modules audio input. Of course there is some electronics involved
where the audio out of the GSM module is connected to the equipment's
PSTN output.

What I am thinking following the discussion here is that I need to
take
my 300baud FSK and convert it to a digital data stream (using
Microprocessor
and zero crossing detector) and use the data communication
capabilities of my
GSM modem to send the data to my PC modem. Then, of course, I will
also need
to take the returned data from my PC modem and convert it to FSK
(using Microprocessor and tone generator) for the equipment.

There will also be a requirement to do the tonal handshaking required
by the 300 baud FSK modem before communications begins. This can be
achieved with the
Microprocessor being used.

Now that sounds like a lot of work but I think I could be guaranteed
that it would function.

In all this I am assuming that when communicating with my PC modem
from
my GSM modem that the network is taking care of the change in
protocols
required. Is my understanding clear with this?

Many thanks again

Denis
_____________________________
http://www.CentronSolutions.com

Relevant Pages

  • Re: 300baud FSK over GSM
    ... at the far end can only communicate at 300baud FSK over the PSTN ... Our end will work with GSM and needs to communicate at the 300 baud ... We are connecting a board to this equipment which will have a GSM ... module (modem) on it. ...
    (sci.electronics.design)
  • Re: 300baud FSK over GSM
    ... > We are connecting a board to this equipment which will have a GSM ... > Our end will be a standard PC with a PC modem(connected to PSTN)." ... modem or is essentially a GSM phone that contains Hayes Compatible one (e.g. ...
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    (sci.electronics.design)
  • Re: 300baud FSK over GSM
    ... > We are connecting a board to this equipment which will have a GSM ... > Our end will be a standard PC with a PC modem(connected to PSTN)." ... In a system of three devices, all of them being a modem, something ... > communication capabilities of my GSM modem to send the data to my PC ...
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  • Re: 300baud FSK over GSM
    ... > We are connecting a board to this equipment which will have a GSM ... > Our end will be a standard PC with a PC modem(connected to PSTN)." ... In a system of three devices, all of them being a modem, something ... > communication capabilities of my GSM modem to send the data to my PC ...
    (sci.electronics.design)