Hi,

Just got my pmdx 122 breakout boards, only to find that the cable connectors are female... so the male to male cables I bought are no good.
I have 2 25 pin to 36 pin printer cables, one of which is the type where you can disassemble the 25 pin end, and resolder the pins in whatever order you want.

For Mach I need 'straight through' cables, right? does that mean pin 1 to pin 1, right up to pin 25 to pin 25, and then 10 empty pins from 26 to 36 on the male end? My standard printer cable connects as per below; is this not suitable?

18  17  16  15  14  13  12  11  10   9    8    7   6    5    4   3    2   1                 
36  35  34  33  32  31  30  29  28  27  26  25  24  23  22  21  20  19

13  12  11  10   9    8    7    6   5    4    3    2   1
   25  24  23  22  21  20  19  18  17  16  15  14   


DB25  Centronics

1       13
2       12
3       11
4       10
5       9
6       8
7       7
8       6
9       5
10     4
11     3
12     2
13     1
14     25
15     33
16     32
17     36
18     34
19     19
20     21
21     23
22     25
23     27
24     29
25     31   

If I've got the pin order on either of the top diagrams wrong, please let me know, and I'll correct them and rewrite the pins table, so it makes sense...

Richard B 

Which part of your system uses a centronics plug.  Never seen that before.  Every controller and BOB I've seen uses DB25 connectors as does the PC.  To answer your question, you should be using a 1:1 cable where pin 1 maps to pin 1, pin 2 to pin 2....... pin 25 to pin 25.  If you need a centronics plug on one end, I'm not sure how the DB25 would map to that.

Thanks rrc,

I thought the pins would have to map 1:1.
The breakout boardshave sockets for IDC26 and what I guess is a 36 pin centronics (see photo attached.) I think I'll use the male to male cables and buy 2 db25 to IDC26 interfaces. That way I don't ave to pll cables apart.

Richard B

I think I would just get a proper cable, think the last time I bought one it was around £3

Hood

I was thinking that if the outboard ends of the parallel to IDC interfaces had a mounting plate on them, bolted to the casing, it would mean the cables wouldn't be pulling against the breaker board itself if I ever accidentally move the pc without checking whether the cables are disconnected... I have to make allowances for my own daftness when I build anything!