[GreenKeys] Teletype Devices for the Deaf (TDD)

[Don Robert House]

Illinois Bell had a 28 KSR Teletype for the Deaf in the headquarters 
lobby at one time.  It was painted a beige... although in the 
lighting it looked pink.  It had a modern Bell symbol on it and was 
connected to a TDD modem via a pair of Tip/Sleeve plugs and jacks.  I 
got the machine but not the modem.  At the time I did not understand 
why the modems were different than the standard F1 and F2 
frequencies.  The only thing I can think of is they did not want them 
to be used commercially by connecting to TWX machines.

Schools for the deaf in Illinois, Indiana, Ohio, Michigan, Wisconsin, 
Arizona and New Mexico once used both M15s and M28s modified for them 
by the Telephone Pioneers of America.  Probably in other states as 
well.  The biggest problem with using a Teletype was the lack of 
portability.  Some Model 42s were carried by deaf people, but not for 
long.

TDD is a relatively new acronym.  All of the signs on the expressways 
in Illinois read "TTY" where compatible pay phones are located.

Don

TTYMAN
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Don Robert House
North American Data Communications Museum
URL: http://www.nadcomm.org
Computer Museum of America
URL: http://www.computer-museum.org