On Dec 29, 15:46, David Gesswein wrote:
> >From: pete_at_dunnington.u-net.com (Pete Turnbull)
> >> 40 pin connector is numbered
> >>
> >> 1 (A) 39 (UU)
> >> 2 (B) 40 (VV)
> >
> >ObNitpick: That's the reverse of the conventional numbering; Berg
> >connectors with letters have the red stripe at the A end, which is on
the
> >left of the pin header (looking into the pins) while all other headers
> >which are numbered have pin 1 on the right.
>
> Yup, how about
> Looking into pins of 40 pin male connector numbering is
>
> 2 (A) 40 (UU)
> 1 (B) 39 (VU)
>
> I think both the numbers are letters were otherwise correct, just the
> summary diagram was wrong.
That wasn't what I meant. Berg label the connector pins starting from the
opposite end of the connector from the rest of the world, so what I meant
was that on actual connectors, the pins are:
39 (B) ... 1 (VV)
40 (A) ... 2 (UU)
or more completely:
39B 37D 35F 33J 31L 29N 27R 25T 23V 21X 19Z 17BB 15DD 13FF 11JJ 9LL 7NN
5RR 3TT 1VV
40A 38C 36E 34H 32K 30M 28P 26S 24U 22W 20Y 18AA 16CC 14EE 12HH 10KK 8MM
6PP 4SS 2UU
Thus on a cable with a Berg connector, the stripe corresponds to pin A and
goes on the left (as you look into the male connector), and on any other
similar connector (3M, T&B Ansley, ITT, Amphenol, Fujitsu, Molex, etc pin
headers but not D-connectors, for example) the stripe corresponds to pin 1
but goes on the right. That's one of the reasons so many DEC cables have a
"THIS WAY UP" sticker.
Of course, if you use the conventional numbering above, you need to change
your table as well (I've put the numbers in brackets, since it IS a Berg
connector, after all):
DB25 40 pin header
1 C (38)
14 D (37)
2 H (34)
15 J (33)
3 M (30)
16 N (29)
4 S (26)
17 T (25)
5 W (22)
18 X (21)
6 AA (18)
19 BB (17)
7 EE (14)
20 FF (13)
8 KK (10)
21 LL (9)
9 PP (6)
22 RR (5)
10 SS (4)
23 TT (3)
11 UU (2)
24 VV (1)
I've put AA where you had CC -- both are ground on the M7744, but it seems
more logical to pair AA and BB, rather than BB and CC.
--
Pete Peter Turnbull
Network Manager
Dept. of Computer Science
University of York
Received on Fri Dec 29 2000 - 20:50:56 GMT