decserver 550 in Kansas City

From: Peter Turnbull <>
Date: Fri Feb 28 15:14:01 2003

On Feb 28, 10:23, Jochen Kunz wrote:
> [ plain text
> Encoded with "quoted-printable" ] :
On 2003.02.28 07:00 Stuart Johnson wrote:
> > Jonathan, what I want to know is how do you connect the RX50 and
> > RD(whatever) hard drive to the RQDX3?
> There are different distribution panels that split the 50 pin cable
> the RQDXx. The M9058 dist panel for the BA123 looks like a double
> card and sits in "QBus slot 13" in the BA123. The BA23 dist panel is
> mounted inside the enclosure on the back of the QBus backplane. I
> the wiring of this panel, I can mail it to you when you want to build
> your own dist panel. There is a BA213 dist panel that replaces the
> panel in a BA213 and has some additional switches LEDs to reset the
> etc. I think it is not that easy to rebuild this.

It's not that hard to make something that will work. The distribution
panels that split up the signals from the RXDX1/2/3 boards to connect
to RDxx or RX50 are mostly just rerouting signals (some include some
buffering). I've made up two of my own; one simple one, on Veroboard
(stripboard), and one as a PCB. If you look in

you'll find the PCB layout and component overlay, along with the RQDX
pinouts, for the larger of the two I made. It includes provision for
switches or jumpers to do the job of the front panel switches. The
circuits for the switches, inbcidentally, are very simple -- a latching
switch, LED, one transistor (to invert the signal, as I recall) and a
few resistors. It needn't even be as complex as that.

I once traced out and re-drew the schematic of the M9058 board, but I
can't find the PostScript file now :-( If I ever do, I'll post it on
the website as well.

Pete						Peter Turnbull
						Network Manager
						University of York
Received on Fri Feb 28 2003 - 15:14:01 GMT

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