Specifications

Chapter 1 - Overview RS-422 And RS-485 Applications Ebook
Page 12 of 137 Manual Documentation Number: <DocNumber>
www.bb-elec.com/
www.bb-europe.com/
When the driver output voltage is measured differentially, the voltage
on the A (-) terminal with respect to the voltage on the B (+) terminal
is negative when in the idle state. Typically this voltage is expressed as
V
AB
. RS-422 and RS-485 drivers produce a voltage somewhere between
2 to 6 volts across their A (-) and B (+) output terminals. The exact
value may vary depending on the power supply voltage, number of unit
loads (UL) connected to the output and termination/biasing
arrangement. For more information on termination and biasing refer to
System Configuration (on page 23).
Figure 5: Measuring Balanced Outputs