[GreenKeys] Teletype Devices for the Deaf (TDD)

[Gregory W. Moore]

All:
I have a M28, which was originally configured for TDD, and have the 
(operating)modem. This is one of the old types that uses the acoustic 
coupling where one places the phone handset into two grommeted 
depressions, one with a microphone, one with a speaker.
    I will make a test and see just what the tones are, as I use MixW 
for the digital modes, and have a very good waterfall display. I have to 
see if my mic on the puter is sufficient to get good readings on the tones.
73 de Greg WA3IVX

Gary Chatters wrote:

>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
>
>
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