Interference Considerations
When wires are run for any significant distance, there is a risk of receiving stray signals on the wires as
interference. If interference signals are strong, it results in data errors or equipment damage.
The following sections describe the sources of interference and how to minimize their effects on the chassis.
Electromagnetic Interference
All the equipment that is powered by AC current can propagate electrical energy that can cause EMI and
possibly affect the operation of other equipment. The typical sources of EMI are equipment power cords and
power service cables from electric utilities.
Strong EMI can destroy the signal drivers and receivers in the chassis. It can even create an electrical hazard
by causing power surges through the power lines into installed equipment. These problems are rare, but could
be catastrophic.
To resolve these problems, you need specialized knowledge and equipment that could consume substantial
time and money. However, you can ensure that you have a properly grounded and shielded electrical
environment, paying special attention to the need for electrical surge suppression.
Radio Frequency Interference
When electromagnetic fields act over a long distance, radio frequency interference (RFI) may be propagated.
Building wiring can often act as an antenna, receiving the RFI signals and creating more EMI on the wiring.
If you use a twisted-pair cable in your plant wiring with a good distribution of grounding conductors, the plant
wiring is unlikely to emit radio interference. If you exceed the recommended distances, use a high-quality
twisted-pair cable with one ground conductor for each data signal.
Lightning and AC Power Fault Interference
If signal wires exceed the recommended cabling distances, or if signal wires pass between buildings, you may
encounter a lightning strike on the chassis.
The electromagnetic pulse (EMP) generated by lightning or other high-energy phenomena can couple enough
energy into unshielded conductors and damage or destroy electronic equipment. For such problems, you must
consult with RFI and EMI experts to ensure adequate electrical surge suppression and shielding of signal
cables in your operating environment.
Tools and Equipment
You need the following tools and equipment to install and upgrade the device and its components:
• ESD-preventive cord and wrist strap
• Antistatic mat or antistatic foam
• Number 1 and Number 2 Phillips-head screwdrivers
• #12-24 pan-head screws to secure the device to the equipment rack.
• Cables for connecting to network ports (based on the configuration)
• Ethernet hub, switch, or PC with a network interface card for connecting to the Ethernet ports
• Console terminal that is configured for 9600 baud, 8 data bits, no parity, no flow control, and 1 stop bit.
• Console cable for connecting to the console port
Cisco NCS 540 Router Hardware Installation Guide
16
Prepare for Installation
Interference Considerations
