Electromagnetic Interference
The following sections describe the sources of interference and how to minimize their effects on the router
system.
Electromagnetic Interference
All the equipment 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 utility companies.
Strong EMI can destroy the signal drivers and receivers in the router and 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 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
should consider the effect that a lightning strike in your vicinity might have on the router.
The Electromagnetic Pulse (EMP) generated by lightning or other high-energy phenomena can couple enough
energy into unshielded conductors to damage or destroy electronic equipment. If you have previously
experienced such problems, you should consult with RFI and EMI experts to ensure that you have adequate
electrical surge suppression and shielding of signal cables in your router operating environment.
Tools and Equipment
You need the following tools and equipment to install and upgrade the router 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 router to the equipment rack
• Cables for connecting to the network ports (depending on the configuration)
• Ethernet hub, switch, or PC with a network interface card for connecting to the Ethernet ports
• Console terminal (an ASCII terminal or a PC running terminal emulation software) that is configured
Prepare for Installation
6
for 115200 baud, 8 data bits, no parity, no flow control, and 1stop bit
Prepare for Installation