27 Jul
2013
27 Jul
'13
11:10 p.m.
So the MMJ cable has the two ends connected in the same orientation, which
as you point out, would effectively swap the signals and make it a null
modem cable. So, I've confirmed that.
The MMJ to DB9 (female) adaptor is a 3rd party product, so I don't know.
BUT, what I do know is that a DEC H8575 doesn't work without a null modem
between it and the PC.
-----Original Message-----
From: Tothwolf
Sent: Saturday, July 27, 2013 10:10 PM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: VAXstation 4000/90
On Sat, 27 Jul 2013, David Cooper wrote:
OK, got my 4000/90 working. Here's what you do:
[1] Download the operator's manual from:
http://deathrow.vistech.net/~cvisors/DEC94MDS/vaxoginb.pdf
[2] The key section here is "A?6 Alternate Start-Up Procedures"
[3] So, you use the "printer" port as the console. This makes sense
because
console terminals of old were hard copy terminals such as a DECwriter
terminal. The "printer" port is the MMJ connector. I have a dual ended
MMJ
connector plugged into an MMJ to DB9 adaptor connected to my laptop to a
USB
--> DB9 device. I'm pretty sure the USB to DB9 is the standard PC wiring,
although I'll have to check that. What I don't know is whether the MMJ
cable
is null modem or not or weather the MMJ to DB9 is null modem or not.
MMJ cables are effectively always null modem because the orientation of
the modular plugs on the cable mirror or flip the signals from one end of
the cable to the other. This is the key to both the system's flexibility
and simplicity. Are you just using a H8571-J MMJ to DE9 adapter at the PC
end?