"Radium" <glucegen1@excite.com> wrote in message 
news:1159040719.275122.178280@m7g2000cwm.googlegroups.com...
> Hi:
>
> EDT [European Deaf Telephone] is the TDD protocol used in Switzerland.
> Where can I find technical information about the EDT? Also, I would
> like to hear some tones resulting from the remote EDTs located in
> Swizterland. I live in USA, so if I dial an EDT number to Switzerland,
> I will hear both the EDT tones as well as the tones resulting from
> negotiations among international telephone exchanges. Those textphone
> and international exchange tones give me an eerie feeling which I
> enjoy. I get a feeling of pleasant fear. Its give me a psychedelic
> sensation. I like it. The tones are scary yet fun -- much like virtual
> reality, a roller-coaster, or a trip to outer space!
>
> If I could find accurate recording of those tones [tones from remote
> Swiss EDTs and international exchange negotiations] on a website in
> Wave format and at least 44.1 khz sample rate and 16-bit, then I would
> just download those tones and listen. Unfortunately, no internet site
> has recordings of those tones.
>
>
> Thanks,
>
> Radium
>

It's a long time since I had anything to do with this but the 'normal' 
standards were/are Baudot, CCITT and EDTN.  There are a number of 
manufacturers of "TypeTalk" equipment and there are some proprietary 
extras - but most systems will interwork.  I also doubt that you are hearing 
any tone negotiation between international exchanges, The in band signalling 
systems CCITT5 (AC10), CCITT4, CCITT R2 and CCITT R2D were all phased out 
years ago as CCITT 7 came in.  CCITT (now ETSI)specifications are available 
free from the ETSI web site - but you may have trouble finding what you 
want.

Peter