12.009 I would like to make my own SCSI cable. Does anyone on csa2 know the pin-out for the standard 50-pin SCSI cable?
Description
This article is from the Apple II Csa2 FAQ, by Jeff Hurlburt with numerous contributions by others.
12.009 I would like to make my own SCSI cable. Does anyone on csa2 know the pin-out for the standard 50-pin SCSI cable?
The cable pinout is documented in the technical reference manual for the
Apple High-Speed SCSI card (and the original one as well).
This pinout is not a simple mapping from one end to the other; it is NOT
easy to make one of these yourself. Apart from any issues of wiring errors,
you also need a properly shielded cable to minimise noise being picked up or
radiated. You should definitely not use a ribbon cable.
Here is the pinout, assuming I haven't made any typos (I can't see any).
DB-25 50-pin Function
1 49 -REQ
2 46 -MSG
3 50 -I/O
4 45 -RST
5 44 -ACK
6 43 -BSY
7 16,18,19 Ground lines
8 26 -DB0
9 20,21,22 Ground lines
10 29 -DB3
11 31 -DB5
12 32 -DB6
13 33 -DB7
14 1,2,3 Ground lines
15 48 -C/D
16 4,5,6 Ground lines
17 41 -ATN
18 7,8,9,11 Ground lines
19 47 -SEL
20 34 -DBP
21 27 -DB1
22 28 -DB2
23 30 -DB4
24 23,24,25 Ground lines
25 38 TERMPWR
The unlisted pins in the 50-pin connector (10, 12, 13, 14, 15, 17, 35, 36, 37,
39, 40, 42) are ground.
Note: the numbers for the 50-pin connector are counted along each row, like a
Dsub-25. They are NOT the wire numbers in a ribbon cable.
By: Steve Reeves
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