SCSI definitions

Front panel SCSI definitions

The SCSI connectors on the front panel.

The bottom SCSI connector is the connector closest to the PCB and the top SCSI connector is furthest away from the PCB (as seen from the front).

I will attempt to describe the connectors throughout this documentation in this way.

Notes on standard pinout for dual SCSI connector

The two connectors are reversed with respect to each other. One connector pinout is therefore is reversed on the PCB, see diagram below, please not "POSN 1" for each connector.

figure, 68 way SCSI connector viewed from below.

(please note PCB layouts in this web area are viewed from above)

Note, the pinouts for the top and bottom SCSI connectors must be identical. This implies that since the top and bottom connectors are reversed that one cable must be rotated 180 degrees before insertion. This will then produce a rotational force on half the cables which must be dealt with adequately on the readout board and must be accommodated on the VFE-PCB. This force can be quite large considering the possible thickness of the cable bundles and total number of cards and cable bundles.