know the pinout 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 connecto
