pdp11/93 DB9 rs232 pinout

Noel Chiappa jnc at mercury.lcs.mit.edu
Sat Nov 15 05:43:50 CST 2014

    > From: Henk Gooijen

    > I wanted to connect a VT510 to the console port. All connectors are
    > DE-9

Really? The PDP-11/94-E User Guide (EK-PDP94-MG-001), available online in a
number of places, shows (pg 46, aka 2-18) the Console/SLU panel, and the
Console connector is much larger than the SLU connectors. (The illustration
shows a 23-pin D-type connector - presumably an error, it should have been
25.) And here:


is a picture of one, and it indeed has the 25-pin console connector.

Although I suppose it's possible they changed the actual hardware at some
point, and some real machines have a 9-pin D-type? Or maybe a VAX of some
sort uses a similar panel, but with all 9-pin D-types, and someone had
stuck on of those on that machine?

    > What worked for me is the "VAX console cable", in other words: that
    > DE-9 connectors is NOT "PC alike"! You can find the VAX console cable
    > pinout on the web.

Good catch! It makes sense that the VAX and 11/93-94 use the same 9-pin
D-type pinout; that way they'd only have to have one kind of cable.


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