6 May
1999
6 May
'99
7:11 a.m.
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.