A.1 Physical Specifications

(2)Physical specifications

 

 

 

 

Table A.1 SCSI physical specifications

 

 

 

Item

 

 

 

 

Specification

 

 

 

 

 

 

 

Driver/Receiver

 

Single-ended

 

 

 

 

 

 

 

 

Connector

 

 

50 Contact Shielded Low Density

 

 

 

 

 

 

 

 

 

Cable

 

 

Max. cable length

 

6 m

 

 

 

 

 

 

 

 

 

 

 

 

Characteristic

 

132 Ω

 

 

 

impedance

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Cable type

 

25 signal twisted pair

 

 

 

 

 

 

 

 

 

 

 

 

Stub wire

 

0.1 mm (from main cable in scanner to internal wiring)

 

 

 

 

 

 

 

 

Signal

 

Terminator

 

See the figure under (3).

level

 

 

 

 

 

 

 

 

 

 

Driver/receiver

 

Open collector or three-state driver

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Output characteristics

 

Low level (true) = 0.0 to 0.5 VDC

 

 

 

 

 

High level (false) = 2.5 to 5.25 VDC

 

 

 

 

 

Output current = 48 mA (corresponding output voltage 0.5 V)

 

 

 

 

 

 

 

 

 

 

 

 

Input characteristics

 

Low level (true) = 0.0 to 0.8 VDC

 

 

 

 

 

High level (false) = 2.0 to 5.25 VDC

 

 

 

 

 

Input load = -0.4 mA max. (at 0.4 V input voltage)

 

 

 

 

 

Input hysteresis = 0.2 VDC min.

 

 

 

 

 

 

 

Connector pin assignments for

 

See (4).

signal lines

 

 

 

 

 

 

 

 

 

 

 

 

 

(3)

Termination

 

 

 

 

 

 

 

 

 

 

+5 V

 

 

 

 

 

 

 

 

 

220 Ω

- signal

330 Ω

Appendix A-3