PDP 11/03

Johnny Billquist bqt at update.uu.se
Mon Nov 9 16:05:06 CST 2015

On 2015-11-09 21:13, jwsmobile wrote:
> On 11/9/2015 4:09 AM, Noel Chiappa wrote:
>>      > From: Jim Stephensn
>>      > I'm looking for a cable or cable pinout to get the console of this
>>      > 11/03 going.
>>      > ...
>>      > It has a M7940-YA DLV11 controller.
>> Hmm. I can't find anything online about the -YA variant of the DLV11; the
>> DLV11 prints (MP00055) don't seem to show it.
>> I don't know exactly wqhat the "extra wires to bring out clock & ..
>> 110/300
>> speed change" entail - and whether you have to have the right jumpers,
>> etc in
>> the Berg connector to make it run?
> the above reference I copied and pasted from Megan Gentry's dec module
> guide
> http://world.std.com/~mbg/pdp11-field-guide.txt
> I don't know what that means either.

I doubt the -YA makes any significant difference here.

> I am mainly asking if I want to hook up a terminal, can I get it going
> with TD, RD and GND (or 2 3 7 on a DB25), or do I need to loop back any
> of the other pins.  Also I will have to figure out the serial settings,
> as Dec was fond of even parity, and so forth.  I figure DEC folks do
> that in their sleep, like others do with the systems they work on
> frequenly.

Normally, you'd call them Tx, Rx and GND, but anyway...
No, you do not need to loop back any signals. DEC didn't like to abuse 
modem control for flow control.

Serial settings... Well, that is essentially a software thing. So it 
depends on the system you have installed. The hardware can of course 
also do different things, but most of the time it's 8N1, and then 
software fool around.
But anything more modern than mid-70s will most likely be 8-bit clean.

> I have several 4 port DLV boards, but want to go with this as a
> reference.  I paid a bit too much for it because it was "working" and I
> don't want to screw it up by replacing cards.  I know even less about
> loading the backplane than I do about hooking up a serial cable.
> I figure worst case I'll get the ribbon cable and wire the lines to a
> DB9 or such and see what happens from there.  I was hoping to get some
> idea whether the correct cable might be available from someone on the
> list first, and buy it, or better, find out how to spot them on ebay.
> I've had a lot of luck with the boards, but none with finding listings
> for cabling.

That would be a DE9. :-)
The information about cabling is in pretty much any DEC manual you'll 
look in. The DLV11 manuals should be on bitsavers even.

> Once I have the full system I got working, I have another full system
> and a power supply I plan to bring to working, then I'll be brave enough
> to start moving things around in the backplane and trying the 4 port
> cards.  Most of them came from the cheap scrap guy, so I don't know the
> state of them as well.  I've seen some people found there were duds in
> the pile.
>> Maybe the easier path would be to buy a different DL-type serial line
>> board
>> (plain DLV11, DLV11-E, DLV11-F, DLV11-J), they're available on eBait
>> for not
>> much money, usually - unless you already have one on hand, of course.
>> (Or did
>> you - for authenticity reasons - _have_ to run the -YA card?)
>> Those are all a known quantity, pinout-wise; the first three all use the
>> standard DL11 cable [same as the UNIBUS one, M7800], the last one uses
>> the
>> smaller header common to the later QBUS machines (e.g. 11/23+, etc).
>> If you have the Berg female shells and pins (not sure if you do; if not,
>> definitely worth getting them, since the cables are basically
>> unobtainable,
>> but fairly easy to make), but don't know the pinout for them, let me
>> know,
>> and I can supply both null-modem and non-null-modem cable diagrams
>> (for DB25
>> connectors, already worked out; I have made DB9 serial cables, but not
>> for
>> direct connection to a DLV11, but could generate those too).
> I'd love that, thanks Noel.  I'm just trying to get as many questions
> answered before I start applying power and squinting at LED's on a
> serial status box, or on a scope.

Note that a -YA normally means it's just a board with a newer revision. 
It do not normally means any change in functionality, except perhaps 
some improvement. But in general totally compatible.


Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt at softjar.se             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol

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