ST506/412 Cable

The ST506/412 interface requires two cables, one for control and one for data. The control cable is shared between the two drives. But each drive has each own data cable. By twisting some wires on the control cable it won't be necessary to set the ID for each drive, since the twist will do the job. Wires 25 to 29 should be twisted between drive 1 & drive 2.

Controller           Drive 2   Twist   Drive 1
+--+                   +--+            +--+
|::|===================|  |============|  |  <-Pin 1
|::|===================|  |============|  |
|::|===================|  |============|  |
|::|===================|  |============|  |
|::|===================|  |=====\/=====|  |
|::|===================|  |=====/\=====|  |
|::|===================|  |============|  |
+--+                   +--+            +--+

Control cable

34 PIN IDC FEMALE (To the Controller)
(To the Drive 2)
(To the Drive 1)

34 PIN IDC FEMALE to the Controller.
34 PIN IDC FEMALE to the Drive 2.
34 PIN IDC FEMALE to the Drive 1.

	Controller	Drive 1	Drive 2
Wire 1-24	1-9	1-9	1-9
Wire 25	25	29	25
Wire 26	26	28	26
Wire 27	27	27	27
Wire 28	28	26	28
Wire 29	29	25	29
Wire 30-34	30-34	30-34	30-34

Data cable

20 PIN IDC FEMALE (To the Controller)
(To the Drive)

20 PIN IDC FEMALE to the Controller.
20 PIN IDC FEMALE to the Drive.

	Controller	Drive
Wire 1-20	1-20	1-20