Subject: Re: DZQ11 ?
To: Brian Murray <>
From: Ken Wellsch <>
List: port-vax
Date: 04/01/1996 22:41:57
| Is the DZQ11 the Qbus equivalent of the unibus DZ11? I have about 20 DZ11
| boards and I would like to get some of them going in my 11/750. So if
| dz.c will work with the DZ11's as well, I'd be a happy beta-tester!

I cannot find my serious tech manuals for DZ series boards, but from what
I can gather scanning a generic DEC comm. handbook, the Q-bus version
is the typical half the number of ports of the Unibus version.  Otherwise
the same control registers and such.  Yeah, I have a serious load of DZ
boards for my Unibus stuff.  The DZV is the first Q-bus implementation
and the DZQ is the second generation version (dual width rather than quad
like the dzv).  Just to keep people confused, a DH-11 is different from
a DHV-11.  The DHV-11 (Q-bus) uses the same register layout as the DHU-11
(Unibus) but does not have quite as many features (the DHQ-11 I am told
is bit selectable to behave like a DHV or a DHU).  The nice aspect about
a DHU is that you can program a delay on receiver interrupts so the
incoming silo can fill and reduce the number of interrupts on heavy
input (e.g. via kermit, my only link to source upgrades and such).
I use an Able QHV clone that I can switch select to a 16ms delay.