Vela CineCast 2000-0422, Installation And User Manual

Page: 29 / 196

Chapter 1 — Getting Started 15
Decoder Installation
SCSI IDs
Typically, each device on a SCSI bus, including the host adapter, must have a
unique SCSI ID. The SCSI ID serves two purposes:
• It uniquely defines each SCSI device on the bus.
• It determines the device’s priority on the bus during arbitration for the bus.
Setting the Decoder’s SCSI ID
The SCSI ID of the CineCast Quad Pro Decoder is set via the SCSI ID selector
switch located on the rear panel. It should be noted that ID7 is usually reserved
for the SCSI initiator (host adapter).
Priority in Arbitrating For the Bus
• Normally, the SCSI initiator (host adapter) is set for SCSI ID 7, which is the
highest priority.
• Each SCSI device on the bus must have a unique SCSI ID.
• Not all host adapters support SCSI IDs 8–15.
• Some host adapters and operating systems have further restrictions on SCSI
IDs for hard disk, CD-ROMs, and tape drives.
• Operating systems and SCSI device drivers may restrict the use of SCSI IDs
to SCSI IDs 0 through 7 only.
Bus Termination
The CineCast Quad Pro decoder includes a selectable built-in terminator; how-
ever, if “hot swapping” of the decoder is anticipated, an in-line SCSI terminator
is recommended. Generally, both ends of a SCSI bus must be terminated.
For systems where only one SCSI cable is used between the host adapter (initia-
tor) and all SCSI devices, the termination is enabled on the host adapter and on
the last SCSI device on the SCSI cable.
For systems where two SCSI cables are connected to the host adapter, the termi-
nation is disabled on the host adapter. The last SCSI device on each SCSI cable
must be terminated.
When mixing both 8-bit and 16-bit devices consult the host adapter’s user manual
for correct termination requirements.