Compaq StorageWorks UltraSCSI RAID Enclosure (DS-BA370 Series) User's Guide (EK-BA370-UG. C02, September 1998)

Single-Ended I/O Module
5–4 UltraSCSI RAID Enclosure
Controlling the Internal SCSI Bus
The I/O module controls the internal SCSI bus in the following
manner:
• Isolates the internal SCSI bus from the external SCSI bus
• Provides single-ended SCSI bus termination for each internal bus
• Disconnects the internal SCSI bus from the external SCSI bus
when directed by the EMU
• Distributes TERMPOWER (+5 V dc) to the internal SCSI bus
• Turns O
N the green internal TERMPOWER LED when internal
TERMPOWER is present
• Turns O
FF the green internal TERMPOWER LED when there is
either an internal TERMPOWER overcurrent condition or no
TERMPOWER
Controlling the External SCSI Bus
The I/O module controls the external SCSI bus in the following
manner:
• Provides single-ended SCSI bus termination for the external bus
• Distributes TERMPOWER (+5 V dc) to the external SCSI bus
• Turns O
N the green external TERMPOWER LED when external
TERMPOWER is present
• Turns O
FF the green external TERMPOWER LED when there is
either an external TERMPOWER overcurrent condition or no
TERMPOWER
• Disables the external bus termination when a cable is connected
to the right VHDCI connector