27 Jun
2006
27 Jun
'06
12:54 p.m.
From: Jules Richardson <julesrichardsonuk at
yahoo.co.uk>
I've got some equipment here that has RS422 serial on it - i.e. it uses
differential signal pairs rather than RS232's reference against ground.
Question is, can I wire up a cable so that I can use an RS232 terminal with
this RS422 equipment? (running over a short distance)
A lot of RS422 equipment uses TTL level to create the +/- signal lines
- hooking it directly to RS232 may blow up your tranceivers, not work,
or both. Or, it may work - I think old Macs were tolerant enough to
do that.
The only "proper" way is to use a RS232 tranceiver chip (like MAX232)
and 422 tranceiver chips (such as 75176(? - it's been a while)) or a
creative arrangement of transistors and resistors.
I can send you a quick schematic if you need.
Joe.