9 Nov
2015
9 Nov
'15
1:48 p.m.
From: Jim Stephensn
> "extra wires to bring out clock & ..
110/300 speed change"
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.
Well, without knowing how those extra pins work, it's very hard to say. Given
that _apparently_ one could change the baud rate externally (which means that
there's something in the cable - or at its other end - to do baud rate
selection), I'd _guess_ that a stock cable probably wouldn't work.
If you find a set of 11/780 prints, that _might_ include the specialized
cable for this beast, but short of that, you're talking signal trace/etc time.
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"
Yes, but it doesn't have the cable!
Trust me, swapping to a DLV11-J is a fully known, simple, approach - not like
trying to work with a serial board with an unknown header pinout!
And that 'working' was some decades back! Who knows what the situation is now!
I don't want to screw it up by replacing cards.
If all you do is replace the M7940 with an M8043 in the same slot, that
shouldn't present a problem (make sure the M8043 is configured properly to be
the console, though; it is, however, very well documented).
I know even less about loading the backplane than I do
about hooking up
a serial cable.
That's OK, I have recently run both M7940's and M8043's in my QBUS systems
here; they are a straight replacement (albeit using different cables - a
40-pin Berg/DuPont connector on the former, and 10-pin Berg/DuPont on
the second one).
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.
Like I say, I expect the cable for the M7940-YA is a special item. As for
cables on eBay - fuhgeddabahtit!
Well, that's not quite true: seller 'conflandard' has some console cables for
sale, but I think only DLV11-J/11-23+ type (they are the same cable,
basically - the header pinout on the two cards is the same, the difference is
that the stock 11/23+ cable allows baud rate selection on the back panel -
but an 11/23+ _will_ work with a stock DLV11-J cable, provided the board is
jumpered correctly).
I've _never_ seen a DL11 type cable (with the 40-pin Berg/Du Pont connector)
for sale on eBay - well, not EIA ones. I think someone had an 20mA one for
sale, once.
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.
_Most_ of the cards I bought from him worked (I haven't been able to try them
all, e.g. I don't have a working UNIBUS machine yet). The one exception was a
DLV11-J on which two of the four serial ports didn't work.
Once you have a working machine/board set, it all becomes much easier, of
course - you can swap boards around and see which ones are working. (If you'd
like, you can send me the DLV11-J, and I'll either send you a known
fully-good one, or test yours and send it back, along with the results. I've
done this for other people here.)
> 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
OK, let me go unearth the cable diagrams - or I suppose I could just look
at a cable, I have a couple of mostly-finished ones on the workbench at the
moment! :-)
Noel