DEC Digital PC 3500 System Reference Manual page 148

To connect SCSI devices, perform the following:
1. Connect the supplied ribbon cable to the appropriate device(s) as shown in
Figure 6-15.
Make sure the cable is connected with the correct orientation. Most cables
and connectors are keyed so you cannot connect them backwards. If your
cable or device is not keyed, you must connect pin 1 of the cable to pin 1 of
the device's connector.
Pin 1 of the cable is on edge with the colored stripe. Pin 1 of the device's
connector should be marked with an arrow at one end of the connector. If
necessary, refer to the device's documentation for pin 1 orientation.
2. Connect the SCSI LED connector cable.
3. Connect a power cable to device.
4. Replace the outside cover.
5. Connect all external devices and restore power.
6. If you want to fine tune some SCSI settings, you can use the SCSI
configuration utility to configure your computer by pressing [Ctrl] + [A] when
the BIOS banner appears during the boot process.
Refer to the documentation supplied with your SCSI device for more information.
Adding Mass Storage Devices
6-29