Sun Microsystems Enterprise 250 Owner's Manual page 87

External SCSI Cabling and Termination
Use the following cabling guidelines to ensure proper device cabling and
termination on the external SCSI bus:
In order to maintain UltraSCSI performance, all cables used must be
UltraSCSI-compliant.
The external SCSI bus must be correctly terminated. Most Sun devices use
autotermination. See the documentation supplied with the device.
If all external mass storage devices use 68-pin connectors, connect all non-Sun
devices to the system first and connect a Sun autoterminating device to the end of
the chain.
If external mass storage devices consist of 68-pin devices and 50-pin devices,
connect the Sun 68-pin devices to the system first and terminate the chain with a
50-pin device and its terminator. The 68-pin device connected to the 68-50 pin
adapter cable must be autoterminating in order to terminate the high-order bits.
Caution – Do not connect 68-pin devices after 50-pin devices; SCSI bus errors
will occur.
The following figures provide a summary of the cabling guidelines.
System
68 - 68
System
68 - 68
Non-Sun Device
68 - 68
Sun Device
68 - 68
Autoterminating
Sun Device
68 - 68
Autoterminating
50-pin device
Sun Device
68 -50
Adapter cable
Chapter 4 Hardware Configuration
Sun Device
T
Terminator
69