HP Integrity NonStop H-Series - Manual (Page 17)

Chapter Two – Installation
Tandem 5142-xSE Rackmount Tape Subsystems User Guide 7
2.2.5 Connect the -48 volt DC power cord to the power connector(s) of the subsystem. There are
independent DC power ports for each drive.
2.2.6 Your hardware is now installed. Refer to your backup software's documentation for instructions
on performing a tape backup.
Note: Make sure that you have terminated the subsystem and have set the subsystem's SCSI ID. (See
Sections 2.3 and 2.5 respectively)
2.3 Terminating the Subsystem
The SCSI bus requires termination to be installed at both ends of the bus. Termination power must be
supplied by at least one device on the bus. Your tape drive subsystem terminates externally using
standard Centronics 50-pin connectors. The two rear panel connectors of drives A or B are
interchangeable. Please be certain to use the correct terminator, a differential, for your host computer
environment. The SCSI terminators are available from Tandem Computers, TapeLabs and other
suppliers of quality components. Your tape drive subsystem has two SCSI connectors to allow the daisy-
chaining of SCSI peripherals. Terminate the last peripheral device on the SCSI bus. Only the last
physical SCSI device on the bus may be terminated. When you have external units attached to the bus,
none of the devices on the SCSI bus can be internally terminated. The following table summarizes the
SCSI termination requirement.
If the tape subsystem is… Then…
the last of multiple devices on the SCSI bus or the
only device on the bus – install the differential or single-ended terminator plug
to the unused rear panel SCSI connector.
in a daisy-chained configuration with other SCSI
devices and is not the last device on the bus – install the terminator on the last device on the bus.
Table 6 SCSI termination requirements
Note: For proper operation of external termination, the host must provide the termination power. If you
experience termination problems, please check your tape controller's termination power fuse.
2.4 Powering the Drive On and Off
Input power for the 5142-xSE tape drive subsystem is controlled by the K-series computer.