U8 switches – Avago Technologies LSI53C120 User Manual
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LSI20101/LSI20102 SCSI Bus Boards
4.4.3 Subsystem Interface Connector J4
A-Side and B-Side SE termination circuitry provides termination for the
SCSI buses. Onboard termination for each of the two physical buses is
controlled in one of two ways: by switches or by the subsystem interface
(J4).
Switches – The LSI20102 board contains the following four switches at
location U8. See
Termination Interface – The termination control on the LSI20102
board permits the connection of a subsystem harness for external control
of the onboard SCSI terminators.
Table 9
U8 Switches
Switch
Position
Condition
Description
SW1
ON
Supplied by LSI20102
SE
OFF
Not supplied by LSI20102
TERMPWR
SW2
ON
Supplied by LSI20102
DIFF
OFF
Not supplied by LSI20102
TERMPWR
SW3
ON
Disabled
SE
OFF
Enabled
Termination
SW4
ON
Disabled
DIFF
OFF
Enabled
Termination