1.3.3 SCSI Activity LED Interface

The SCSI activity LED interface is a four-wire arrangement that allows connection of an LED harness to the board. The connector on the host adapter is J6 for both channels. See Table 3.8 on page 3-12for the signal name and pin numbers on this interface.

1.3.4 Cabling

The cable provided in the kit is matched for a Fast/Ultra/Ultra2/Ultra160 SE or LVD operation. This cable also has built-in multimode (SE/LVD) termination since most Ultra160 hard disk drives are not made with on-board LVD termination.

Table 1.1 lists standard cable specifications.

Table 1.1

Standard Cables

 

 

 

 

 

 

 

 

 

Maximum Bus Length, Meters1

 

 

 

 

 

 

STA Term

 

SE

LVD

Maximum Devices

 

 

 

 

Wide Ultra SCSI

1.5

see note2

8

Wide Ultra SCSI

3

see note2

4

Wide Ultra2 SCSI

see note3

12

16

 

 

 

 

 

Ultra160

 

see note3

12

16

1.This parameter may be exceeded in point-to-point and engineered applications.

2.LVD was not defined in the original SCSI standards for this speed. If all devices on the bus support LVD, then 12-meter operation is possible at this speed. However, if any device on the bus is SE only, then the entire bus switches to SE mode, and the distances in the SE column apply.

3.SE and High Voltage Differential (HVD) are not defined at greater than Ultra speeds.

Interface Descriptions

1-5