Anyone have a spare PDP-11/84 serial console panel they could part with?

Glen Slick glen.slick at
Tue Jul 26 08:53:39 CDT 2016

On Jul 26, 2016 6:11 AM, "Noel Chiappa" <jnc at> wrote:
>     >> a baud rate selection switch
>     > That turns out to be purely off-board (using a clock on the card,
>     > the 'external clock' option on the CPU (same as the 11/23+).
> Ooops, my mistake - I _thought_ it was the same as the -11/23+, but now
that I
> look, it brings the baud rate selection lines out to the daughter card.
> you can select the baud rate without the daughter card - like I said, I
> run -11/84 CPU cards in a stock (Q/CD!) QBUS box.
>     >> a single 20-pin connector for a ribbon cable that attaches to the
>     >> KDJ11-B and MDM.
>     > I'd have to check to see if there's anything critical in there for
>     > controlling the power supplies.
> My guess would be no, since the only things on the serial card that come
> through that cable from the MDM board are the baud rate and force dialog,
> which come from the CPU card through the MDM card. (Why on earth DEC did
> that, instead of just having them come directly from the CPU card, I have
> no earthly idea. Anyone have a guess?)
>         Noel

One thing that needs to happen on the 11/84 is routing the boot diagnostic
LED signals from the M8190 KDJ11-B to the two 7-segment displays on the
front panel instead of to the LED displays on the BA23 console serial panel
of the 11/73, 11/83.

The LED signals and baudrate selection signals are on the same 20-pin
connector on the M8190. To route those to both the 11/84 front panel and
the console serial panel you would either need a split cable, or to route
the connections through a distribution board, which is what they did with
the MDM.

Actually the 11/84 I have is the -E version which did away with the MDM. In
its place there are 5 ribbon cable connectors on the 11/84-E backplane and
routing on the backplane which has similar functions to the MDM. Two of the
connectors are for ribbon cables from the 10-pin and 20-pin connectors on
the M8190. One connector is for the ribbon cable to the front panel, which
contains the LED display signals, among other signals. One connector is for
the 20-pin ribbon cable to the console serial panel. The last connector is
for the 10-pin ribbon cable to the H7204 power supply.

Yes, I should be able to rig up a DEC standard 10-pin SLU cable directly to
the 10-pin connector on the M8190 KDJ11-B and configure the baudrate with
jumpers on the M8190. Getting a real 11/84 serial console panel would be
mainly a cosmetic restoration to the original setup. Just nice to have.


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