Console and Re: More info RE: KA650 & uVAX

From: Eric Smith <eric_at_brouhaha.com>
Date: Thu May 6 14:11:13 1999

Chuck wrote:
> > You quoted the FAQ (which I also read) as needing to connect "ground" to
> > pin 7 but on the MMJ connector there is no "ground" pin. Just the two
> > differential drive TD and RD pairs. This is the question I had, how to
> > handle the ground situation.Do I :
> > 1) Connect TD- and RD- together and then make those ground?
> > 2) Use one of TD- or RD- ?
> > 3) None of the above, do something else?

Allison wrote:
> ?????! Check again, your using RS422 differential not 423.

I don't know anything about DEC MMJ wiring. But various systems use drivers
and receivers that are compatible with both EIA-422 and 423. IIRC, to use
422 drivers for 423, you use the TX- output, and to use 422 receivers
for 423, you ground RX+ and use the RX- input.
Received on Thu May 06 1999 - 14:11:13 BST