Description of cable for Rainbow, with hard-disk controller, to disk. Retyped from Rainbow Technical Manual, Part Number EK-RB100-TM-001 First edition December 1984. "Diagram shows cable, P/N 17-00427-01, with, from left to right, the wider disk-end edge connector, Labelled P2, then the narrower edge- connector, P3, and then the controller card end, P1. Numbering is based on, top left=1, bottom left=2." From Signal Name Mnemonic To ---------------------------------------------------------------------- P1-1 Reduce Write Current RWC L P2-2 P1-2 Ground GND P2-1 P1-3 Head Select 2 HD SEL 2 L P2-4 P1-4 Ground GND P2-3 P1-5 Write Gate WR GATE L P2-6 P1-6 Ground GND P2-5 P1-7 Seek Complete SEEK COMPLETE L P2-8 P1-8 Ground GND P2-7 P1-9 Track 000 TK 000 L P2-10 P1-10 Ground GND P2-9 P1-11 Write Fault WRITE FAULT L P2-12 P1-12 Ground GND P2-11 P1-13 Head Select 0 HD SEL 0 L P2-14 P1-14 Ground GND P2-13 P1-15 Direction In DIR L P2-34 P1-16 Ground GND P2-33 P1-17 Head Select 1 HD SEL 1 L P2-18 P1-18 Ground GND P2-17 P1-19 Index Pulse INDEX L P2-20 P1-20 Ground GND P2-19 P1-21 Ready READY L P2-22 P1-22 Ground GND P2-21 P1-23 Step Pulse STEP L P2-24 P1-24 Ground GND P2-23 P1-25 Drive Select 0 DRV SEL 0 L P2-26 P1-26 Ground GND P2-25 P1-27 -MFM Write Data 0 MFM WRITE DATA 0 L P3-14 P1-28 +MFM Write Data 0 MFM WRITE DATA 0 H P3-13 P1-29 -MFM Read Data 0 MFM READ DATA 0 L P3-18 P1-30 +MFM Read Data 0 MFM READ DATA 0 H P3-17 P1 - There are no wires to pins 31-34. Note wires in twisted pairs:- 1 and 2, 2 and 3, etc. P2 - Pins 15,16,27-32, have no wires. P3 - Pins 1-12,15,16,19 and 20 have no wires.