More Information About Termination - TYAN THUNDER K7 User Manual

More information about termination

The last SCSI device on the end of each SCSI bus cable must be terminated, and termination must be
disabled for all other devices in the middle of the cables. Ultra160 and Ultra2 SCSI devices are automat-
ically un-terminated, but Ultra SCSI and Fast/Wide SCSI devices do have termination that you must
check. For more information, refer to the documentation for each SCSI device. If you are using external
Ultra2 or Ultra160 devices, be sure to use an LVD terminator to terminate the last device in the chain. If
you use a single-ended, active terminator (sometimes called an Ultra terminator) the SCSI devices will
not operate at their maximum speed.
If you have any problems while setting up SCSI devices, check the following items first:
• Are all SCSI devices powered on?
• Are all SCSI cables and power cables properly connected?
• Does each device on each SCSI bus have a unique SCSI ID?
• Does the total SCSI cable length exceed the maximum allowable length? (See table below.)
• Is the SCSI bus properly terminated?
If you are still unable to resolve a problem, contact your vendor for help.
Maximum Cable Length
25 m (82.0 ft)
12 m (39.4 ft)
3 m (9.8 ft)
3 m (9.8 ft)
3 m (9.8 ft)
1.5 m (4.9 ft)
* Mixing Fast/Ultra devices with Ultra160 and Ultra2 SCSI devices causes the entire SCSI bus to default
to Ultra SCSI speeds and cable length requirements.
** Ultra SCSI data transfer rates do not currently support more than seven devices connected to the
SCSI card.
Thunder K7 S2462
Maximum Cable Lengths
Data Transfer Rate
Ultra160 SCSI (160 MBytes/sec)
and Ultra2 SCSI (80 MBytes/sec)
Ultra160 SCSI (160 MBytes/sec)*
and Ultra2 SCSI (80 MBytes/sec)
Fast Wide SCSI (20 MBytes/sec)
Fast SCSI (10 MBytes/sec)
Ultra SCSI (40 MByes/sec for 16-
bit, 20 MBytes/sec for 8-bit)
Ultra SCSI (40 MByes/sec for 16-
bit, 20 MBytes/sec for 8-bit)
Maximum Devices Supported
1
15
15
7
4
5-7**
51