|----------------------------| CABLES |------------------------------|
|                                                                    |
|            Controller     Drive 2(or none)       Drive 1           |
|                                                                    |
|              1+--+ ---------1+--+ ----stripe-----1+--+ Pins 10-16  |
| FLOPPY cable  |::|===========||||=================|||| are twisted |
| with twist    |::|===========||||=============XX==|||| before the  |
| (control &    |::|===========||||=================|||| connector.  |
| data, 34 pin) |::|===========||||=================||||  (7 wires)  |
|               +--+           +--+                 +--+             |
|              1+--+ ---------1+--+ ----stripe-----1+--+ Pins 25-29  |
| ST412 & ESDI  |::|===========||||=================|||| are twisted |
| Hard Drive    |::|===========||||=================|||| before the  |
| cable w/twist |::|===========||||=============XX==|||| connector.  |
| (control)     |::|===========||||=================||||  (5 wires)  |
|               +--+           +--+                 +--+             |
|              1+--+ -----------stripe-------------1+--+ (no twists) |
| ST412 & ESDI  |::|================================|||| Each drive  |
| Hard Drive    |::|================================|||| has it's    |
| (data, 20 pin)|::|================================|||| own data    |
|               +--+                                +--+ cable       |
|                                                                    |
| IMPORTANT NOTE: Pin #1 on any drive cable SHOULD be indicated by a |
|                 a colored stripe.  If you should find the stripe   |
|                 by connector pin 34 (or 20), inspect the whole     |
|                 cable VERY throughly!                              |
|                                                                    |
| DRIVE SELECT  For both Floppy and Hard drives, when the 34 pin     |
| JUMPERS:      cable has a twist, the device number should be set   |
|               to the second position.  Drives numbered 0-3, set to |
|               1, those numbered 1-4, set to 2.  When cables with-  |
|               out a twist are used, Floppy "A", and(or) Hard drive |
|               "C" should be set to 1, and the second Floppy and    |
|               (or) Hard drive should be set to 2.                  |
|                                                                    |
| TERMINATORS:  When using more than one drive on a cable (ie; 2FDs  |
|               or 2HDs), the terminating resistor pack should be    |
|               left on the drive furthest from the controller, and  |
|               removed from the drive closest to the controller.    |
|                                                                    |
+--------------------------------------------------------------------+

Make sure you don't get a floppy cable by mistake, they are similar.

ST-251 ST412 MFM
                                                          /-4-3-2-1-\
                                                          | O O O O | Power
              o o o o o o o o                             +---------+
  /Data Cable o o o o o o o o  /Controller Cable    1       5 G G 12
 ========= == | | | | | | | | ==================== ===   ============
              | | | | | | | | 1------------+
              | | | | | | | | +-Terminator-+
              | | | | | | | |
Drive Select->1 2 3 4 | | | \ Radial
                | | | | | \-- Reserved
                | \ / | \---- Write Fault
                |  |  \------ Factory Test
                |  \--------- Never Used (Drive Select 3 and 4)
                \ If twisted cable, use Drive Select 2