[comp.sys.next] RS-423 on new machines -- What is it?

irv@happym.UUCP (Irving [h] Wolfe) (09/26/90)

What's RS-423?  I've used RS-232 for nearby serial devices and RS-422 for
terminals 700 feet from the computer, but what is this RS-423 that the new
NeXT machines have, and what can it be interfaced to?
-- 
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fjs@nntp-server.caltech.edu (Fernando J. Selman) (09/26/90)

irv@happym.UUCP (Irving [h] Wolfe) writes:

>What's RS-423?  I've used RS-232 for nearby serial devices and RS-422 for
>terminals 700 feet from the computer, but what is this RS-423 that the new
>NeXT machines have, and what can it be interfaced to?
>-- 
> [stuff deleted]

From the latest Horowitz and Hill, page 727:


		       RS-232		RS-423A		RS-422A
	               ======		=======		=======

Mode	            single-ended	single-ended	differential

Maximun Number
	Drivers          1                    1             1
	Receivers        1	             10            10

Maximun Cable Length	15m                1200m         1200m

Maximun Data Rate(bit/s) 20k                100k           10M

Transmit Levels	      +-5V min		+-3.6V min	+-2V min
		      +-15V max		+-6.0V max	(diff'l)

etc.

			Fernando

henry@zoo.toronto.edu (Henry Spencer) (09/27/90)

In article <688@happym.UUCP> irv@happym.UUCP (Irving [h] Wolfe) writes:
>What's RS-423?  I've used RS-232 for nearby serial devices and RS-422 for
>terminals 700 feet from the computer, but what is this RS-423 that the new
>NeXT machines have, and what can it be interfaced to?

RS-423 is sort of a sexier RS-232, easier to deal with electrically and
capable of rather higher speeds than a standard-conforming RS-232 (many
RS-232 implementations play fast and loose with the standard).  It is
generally compatible with RS-232 if you don't push hard (no long cables,
no K-Mart-price PC-market devices that save $1.95 by implementing only
a vague approximation to RS-232, no connectors made out of bobby pins).
-- 
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