95
CHAPTER 8: Testing Twisted-Pair Cable
8.2.5 N
OISE
Noise is defined as unwanted signals on the segment. Because of the
construction of UTP cable, it acts as an antenna to electromagnetic and
radio-frequency signals (refer to Figure 8-12). Examples of noise producers
are fluorescent lights, electric motors, power lines, signals caused by voice
lines sharing the same pathway as a data line, elevators, and industrial-type
equipment.
Figure 8-12. Noise.
The IEEE 802.3 standard for 10BASE-T includes an impulse noise
specification. If you have selected 10BASE-T as the cable test standard
when performing a noise test, the 802.3 requirements are used for
pass/fail criteria. For all other selected cable test standards, noise will
be measured but will not be judged as pass or fail.
out
in
UV light fixture
Noise
Summary of Contents for SCAN-LAN VI
Page 2: ......