Need serial cabe for pdp 11/34 M7856

Don North north at
Sun Jan 15 12:47:40 CST 2017

On 1/15/2017 10:24 AM, Tony Duell wrote:
> On Sun, Jan 15, 2017 at 5:47 PM, Devin <lyokoboy0 at> wrote:
>> The cable that came with my 11/34 is for current loop, i need a cable that
>> is wired for serial. If no one has the cable, i could make one myself, i
>> just need the 40 pin connector that goes on the cable. I have been unable to
>> find the connector. Oddly ebay appears to have the side of the connector
>> that goes on the M7856 board itself, but i need the other end, that goes on
>> the wire.
> The normal IDC ribbon cable socket, as was used on IDE disk drive cables
> (40 pin) will fit. In an emergency, you can take a length of 3 wire ribbon
> cable, separate the wires and press them onto the right pins of such a
> socket, and use a spare piece of the same wire for the jumper (1489
> output to UART input), agan pressed onto the right pins, Then press the
> whole lot together in a vice. Did that for a DEC serial cable over 25
> years ago
> If you want to do it 'properly' then I think this is the right
> connector housing :
> Yes, 44 pin, there are 2 unused pins at each end. But 40 pin
> ones are made too. And you would need contact pins, which
> are linked from that page.
> That's a UK supplier, I have no idea where you are, but you
> might be able to track it down from the info on that page.
> -tony
Or here is a slightly different approach that I now use. I made up this PCB:  (price is $18 for 3 boards from 

that adapts a standard 40p IDE cable to a 9pin serial connector (M or F, as needed).

So with this approach you can use about any length of standard 40p IDE cable to 
out from the DL11 (I use about 24" lengths to get out of the 11/34 box), the 
adapter, and
then a standard M/F serial cable to a 9p serial port, or a 9p serial port to USB 


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