Parity Check (S3):
If S3 is open, the CD-ROM drive performs an odd parity check on the
input data on the SCSI data bus.
If S3 is shorted, no parity check is performed. A parity bit is added at
all times to the output data from the CD-ROM drive regardless of the
S3 setting.
S512 (S4):
If S4 is open, the drive will operate at 2048 bytes per logical block. If
S4 is shorted, it will operate at 512 bytes per logical block. It is possible
to change the number of bytes per logical block using Mode Select in
the SCSI commands.
Terminator (S5):
The active terminator connected to the SCSI bus becomes valid by
shorting S5.
If S5 is open, the terminator should become invalid and be equivalent
to a state in which nothing is connected.
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2. Controls and Functions