Asus AP100 Hardware Reference Manual - Page 30

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SCSI Cable Limits

SCSI cables have a limit to the length that it may have. Exceeding the length

may cause problems mounting or using any one of the SCSI devices.

CAUTION:

Exceeding the SCSI cable limits may cause unreliable data

transfers even if all the devices mount properly.

NOTES:

•

Narrow refers to 50 pin and Wide refers to 68 pin. Don't get confused

from the width of the connector or cable.

•

The SCSI ID for devices on one connector cannot be the same as the

SCSI ID for devices on the other connectors. None of the devices on any

connector can use ID7, which is reserved for the SCSI controller.

•

A maximum of 15 devices may be connected to the motherboard (three

connectors) at one time. The following "Max Devices" are for individual

connectors and do not take into account other SCSI devices.

Cable Limits

1) 12m (29.4ft)

2) 3m - 1.5m

3) 3m (9.8ft)

4) 3m - 1.5m

5) 3m (9.8ft)

Notes for the above chart:

1) A total of 15 "Ultra2-SCSI" devices (ID0-ID15) may be connected to the 68

pin Ultra2 connector on the motherboard.

NOTE: If connecting Fast/Ultra devices with Ultra2 devices on the Ul-

tra2 connector, the entire SCSI bus will be limited to the Ultra SCSI

conditions listed above. Mixing SCSI devices is highly not recommended.

2) A total of 8 "Wide Ultra-SCSI" devices (ID0-ID15) may be connected to

the 68 pin Wide connector if using a 1.5m (4.9ft) cable, but only 4 "Wide

Ultra-SCSI" devcies if using a 3m (9.89ft) cable. Ultra-SCSI technology

is unstable over long lenghts, therefore stability will depend on they qual-

ity of your cable and devices.

3) A total of 15 "Wide-SCSI" devices (ID0-ID15) may be connected to the

68 pin Wide connector.

4) A total of 7 "Narrow Ultra-SCSI" devices (ID0-ID6) may be connected

to the 50 pin Narrow connector when using 1.5m (4.9ft) cable but only 4

devices when using 3m (9.8ft) cable. Ultra-SCSI technology is unstable

over long lenghts, therefore stability will depend on they quality of your

cable and devices.

5) A total of 7 "Narrow Fast SCSI" devices (ID0-ID7) may be connected to

the 50 pin Narrow connector.

IV. Appendix

Max Data Transfer Rates

Ultra2-SCSI (68 pin 80MB/Sec)

Wide Ultra-SCSI (68 pin 40MB/Sec)

Wide-SCSI (68 pin 20MB/Sec)

Narrow Ultra-SCSI (50 pin 20MB/Sec) 4 - 7

Narrow Fast-SCSI (50 pin 10MB/Sec) 7

AP100 Hardware Reference Guide

Max Devices

4 - 8