Table of Contents
Advertisement
The ground offset voltage between logical ground terminals on any two device connectors shall be
less than 50 mV.
1.11.3
Electrical characteristics of SCSI parallel interface
The Fast-20 parallel interface shall have one of the following electrical characteristics:
1) Either conductor of single-ended driver and receiver, and each signal pair shall be active, and
the other conductor shall be grounded.
2) Both conductors of differential driver and receiver, and each signal pair shall be active.
The single-ended and differential transceivers cannot be used simultaneously.
(1)
Single-Ended type options
a. Termination of single-ended bus signals
All SCSI bus signals are common to all devices connected to the same bus. All signal lines
shall be terminated at their both ends by the terminators which are compatible to the
transceivers used for SCSI devices. The end of bus shall be defined at each end point. The
end point can be inside of an SCSI device.
Single-ended bus signals not defined as RESERVED, GROUND or TERMPWR shall be
terminated at each bus end securely. Each signal termination shall satisfy the following
requirements:
1)
Each terminator shall be powered from the TERMPWR line.
2)
Each terminator shall feed the current to a signal line if the terminal voltage of this signal
line is 2.5 VDC or less. This current shall not exceed 24 mA if the line voltage is greater
than 0.2 VDC even when all other signal lines are driven with the 4.0 VDC power.
3)
Each terminator shall not feed the current to a signal line if the terminal voltage of this
signal line exceeds 3.24 VDC.
4)
All signal lines shall have the voltage of at least 2.5 VDC when released.
5)
The terminator at each end of SCSI bus shall add a 25-pF capacitance maximum to each
signal (see Section 1.11.2).
No terminator shall be used if it connects the 220 Ω resistance to the 5V line and the 330
6)
Ω resistance to the ground.
1-130
C141-C011
Hide quick links:
Advertisement
Table of Contents
