4-4
4.1.2
Physical Specification
Table 4-1
SCSI physical specifications
Item
Specifications
Driver/Receiver
Single-ended
Connector
50 Contact Shielded Low Density
Cable
Max. cable length
6 m
Characteristic impedance
132
Ω
Cable type
25 signal twisted pair
Stub wire
≤
0.1 mm (from main cable in scanner to internal wiring)
Signal level
Terminator
See the figure under (3).
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
≤
0.5V)
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 0.4V input voltage Input
hysteresis = 0.2 VDC min.
Connector pin assignments for lines
See (4).
4.1.3
Termination
220
Ω
330
Ω