Cisco 10720 - Manual (Page 23)

23
Site Wiring Distance and Interference Guidelines
78-13101-02
Translated Safety Warnings
Site Wiring Distance and Interference Guidelines
This section offers site wiring guidelines for setting up the site plant wiring and cabling. When planning
the location of the new system, consider the following:
• Electromagnetic Interference, page 23
• Distance Limitations for Signaling and Unshielded Conductors, page 23
Electromagnetic Interference
Electromagnetic interference can occur between the field and the signals on the wires when the wires are
run for any significant distance. This fact has two
implications for the construction of plant wiring :
• Poor wiring practice can result in radio interference emanating from the plant wiring.
• Strong EMI, especially when it is caused by lightning or radio transmitters, can destroy and/or cause
interference with the signal drivers and receivers in the Cisco 10720 Internet Router, and can create
an electrical hazard by conducting power surges through lines and into equipment.
Note To predict and remedy strong EMI, consult experts in radio frequency interference (RFI).
A good quality twisted pair cable or shielded twisted pair cable helps limit radiation and noise induced
into the cable minimizing,
• Potential for radio interference.
• Potential for interference with the data transmission.
Distance Limitations for Signaling and Unshielded Conductors
Give special consideration to the effect of a lightning strike in the site vicinity if wires exceed
recommended distances, or if wires pass between buildings. The electromagnetic pulse (EMP) caused
by lightning or other high-energy phenomena can easily couple enough energy into unshielded
conductors to destroy electronic devices.
Provide a properly grounded and shielded environment. Consider electrical surge suppression issues by
addressing the following items:
• Potential surge sources
• Distance
Caution Splicing can degrade cable performance.
Translated Safety Warnings
Safety warnings appear throughout this publication in procedures that, if performed incorrectly, may
harm you. A warning symbol precedes each warning statement. The following paragraph is an example
of a safety warning. It identifies the warning symbol and associates it with a bodily injury hazard. The
remaining paragraphs in this section are translations of the initial safety warning.