[GreenKeys] Teletype Devices for the Deaf (TDD)

[Gary Chatters]

On Mon, 24 Feb 2003, Charles Ring, W3NU wrote:

>
>
> is this standard still in use now with the electronic TDD devices, and are the
> old machines/modems still compatible?
>

I think that the current TDD system is mostly the same, but I do not keep
up with the technology, so can't say anything definitive.  BTW, my
statement that the TDD modems only use one-tone with OOK may not be
correct.  They are simpler than the two tone pairs of a 103 modem, but I
am not sure of the details.  You can do a web search and find more
information.  Here is one URL: http://tap.gallaudet.edu/TTY-Basics.htm

Gary