INSTALLATION .III

Connectors

III. INSTALLATION

SCSI Connection and Termination Information

Each SCSI channel is like a water hose where the inside must be opened and the ends must be closed. Each connector, whether 68 pins or 50 pins may have single or double-ended configurations. For Single-Ended configurations, the Termination for that particular channel must be set to Enabled in BIOS PNP AND PCI SETUP. For Double-ended configurations, the Termination for that particular channel must be set to Disabled in BIOS PNP AND PCI SETUP. Each channel may have up to 15 Ultra2 or Ultra-Wide 68-pin devices (ID#0-15, with #7 reserved for the chipset). Channel B may have up to 7 Ultra-Fast 50-pin devices (ID#0-6, with #7 reserved for the chipset), but channel B’s 68-pin devices must be deducted by the number of 50- pin devices because each channel can only have up to 15 SCSI devices.

IMPORTANT: SCSI devices of different speeds mixed on the same channel will bring all the other devices on that channel down to the slowest speed. Because the 50-pin Ultra-Fast connector is shared on Channel B, the fastest that can be attained on the Channel B 68-pin Ultra2 connector is equal to the slowest device between the two connectors. Basically, if you want to use both Ultra2 devices and Ultra-Fast devices, use the 68 pins on Channel A and the 50 pins on Channel B. Do not use the 68 pins on Channel B in this case.

NOTE: Ultra2 devices do not have termination jumpers so a terminator block on the SCSI cable is needed. If your end devices have its own termination, you may use it instead.

SCSI Connection Examples

(External Cable)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

External SCSI

 

SCSI Deivice

 

SCSI Deivice

 

 

 

 

 

 

 

 

 

Cable Conn.

 

(no termination)

 

(Terminated)

 

 

 

 

Chassis

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Internal to

 

SCSI Deivice

 

Termination

 

Disable Termination in BIOS

 

 

External Conn.

 

(no termination)

 

Block

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

68pin or 50pin Connector

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(Internal Cable)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Double-Ended Configuration

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

SCSI Deivice

 

SCSI Deivice

 

Termination

 

Enable Termination in BIOS

 

 

(no termination)

 

(no termination)

 

Block

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

68pin or 50pin Connector

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(Internal or External)

Single-Ended Configuration

30

ASUS XG-DLS User’s Manual