Specifications

Chapter 1 - Overview RS-422 And RS-485 Applications Ebook
Page 9 of 137 Manual Documentation Number: <DocNumber>
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real data. Characteristics such as the bandwidth and amount of
attenuation in the media, the amount and type of noise, and the
sensitivity of the receiver to the signal and noise, affect the maximum
possible data rate and transmission distance.
Unbalanced Data Transmission
To understand the advantages of balanced data transmission used in
RS-422 and RS-485 systems it is helpful to review the characteristics
and features of unbalanced data transmission.
RS-232 is an unbalanced transmission standard. Each signal that
transmits in an RS-232 system appears on the interface connector as a
voltage with reference to a signal ground. For example, the transmitted
data from a DTE device appears on TD with respect to GND. (When
using the connector specified in the EIA-232 standard (DB-25) these
signals are found on pin 2 and pin 7 respectively.)