[RTTY] When did mechanical teleprinters become obsolete?

[Bill Coleman]

I was just thinking (dangerous, I know) this morning about the  
history of RTTY, and I wondered exactly when did the use of  
mechanical teleprinters become obsolete? Now, back in 1975, there was  
a fellow who adapted a terminal unit to an Altair 8080 and was  
participating in the BARTG contest while he was exhibiting at an  
Altair competition. He won the price for the best application of the  
Altair computer.

So, that's probably the earliest mechanical teleprinters were  
replaced -- but when was the last year that they were used on the air?

Bill Coleman, AA4LR, PP-ASEL        Mail: aa4lr at arrl.net
Quote: "Not within a thousand years will man ever fly!"
             -- Wilbur Wright, 1901