Leonard Erickson wrote in a message to Roy J. Tellason:

 LE> (two of the characters are equivalent to the ASCII SI and SO 
 LE> characters and cause the carriage to "shift" the way old 
 LE> mechanical typewriters did when you hit the shift key.

 RJT> Yeah,  "letters" and "figures".

 LE> With at least three different sets of "figures" characters.
 LE> "regular", "stock market" and "weather".

I'd forgotten all about that...



 LE> Well, consifder that the TTY units used 20 mA current loop in many
 LE> cases, /*not* RS-232. (BTW, the old IBM PC Asynch cards have
 LE> jumpers for running them as 20 mA current loop instead of RS-232!
 LE> They use pins not used by RS-232)

The first system I worked with was like that,  used a DECWriter as a system
console.  Then there were devices out there,  somewhat earlier I guess, 
that used a 60mA current loop.

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