The 9552AI is a SCSI-2 active terminator
for "single-ended" SCSI bus subsystems,
to be mounted internally on the ribbon
Every SCSI bus must have a terminator
(terminating resistors) at each end
of its internal and/or external bus.
This extra step is what allows SCSI
to operate at speeds well beyond that
of its contemporary, IDE/ATA (both systems
are now obselete, replaced by SAS and SATA,
Active termination uses a sophisticated
method of terminating the SCSI bus to
allow for faster speeds and longer cable
lengths than does passive termination.
This terminator is mounted on a Dual-Row
50-pin Socket connector.