Qbus Backplanes

From: Ethan Dicks <erd_6502_at_yahoo.com>
Date: Thu Jun 5 09:33:00 2003

--- vance_at_neurotica.com wrote:
> Hello people. Is there any way to tell if a backplane is QQQQ or QQCD by
> looking at it, and without having to pull the backplane out of the
> chassis?

Not from the slot-side... all the connectors look exactly the same.

Well... not _visually_ You could sit down with a VOM or a continuity
tester and probe a couple of selected pins to determine the wiring
scheme. In practice, though, it's ordinarily done by other means.

In some older chassis, you can see the backplane wiring, but not on
boxes like the BA23 or BA123.

> What if I can find the model number of the chassis?

That's useful... The model numbers that look like BA-23, BA-11N, BA-11M,
etc., are the ones you want.

Also, remember in newer boxes, it's three slots of Q22-CD, with the rest
Q22-Q22. Older boxes can be wired for either 18-bit or 22-bit addressing,
which may or may not involve Q-CD slots. I _think_ the BA-11N is a 18-bit
Q-CD box... that's what I remember my 11/23 is in (but I added the extra
wires some time ago to make it Q22).

-ethan
Received on Thu Jun 05 2003 - 09:33:00 BST