Physical specification

Table 3.1 SCSI physical specification

Item

 

Specification

 

 

 

Driver/receiver

Single Ended

 

 

 

Connector

50 Contact Shielded Low Density

 

 

 

Cable

Max. cable length

6 m

 

Characteristic impedance

90 Ω to 140 Ω

 

 

 

 

Cable type

25 signal twisted pair

 

 

 

 

Stub length

≤ 0.1 m (from mainline)

Signal

Terminator

See Figure. 3.2

level

 

 

Driver/receiver

Open collector or three states driver

 

 

 

 

 

Output characteristics:

 

 

Low-level output voltage

0.0 to 0.5 volts dc at 48mA sinking

 

 

(signal assertion)

 

High-level output voltage

2.5 to 5.25 volts dc (signal

 

 

negation)

 

Input characteristics :

 

 

Low level input voltage

0.0 to 0.8 volts dc

 

High level input voltage

2.0 to 5.25 volts dc

 

Low level input current

–0.4 to 0.0mA at Vi=0.5 volts dc

 

High level input current

0.0 to 0.1mA at Vi=2.7 volts dc

 

Minimum input hysteresis

0.2 volts dc

 

 

 

Connector pin assignments for

See Table 3.2

signal lines

 

 

 

 

3-4

M3099GX/GH OEM Manual