The extent of your network and the distances between the network interface connections depend, in part, on
the following factors:
•
Signal type
•
Signal speed
•
Transmission medium
The distance and rate limits referenced in the following sections are the IEEE-recommended maximum speeds
and distances for signaling purposes. Use this information as a guideline when planning your network
connections
>prior to
installing the Cisco ASR 902 Router.
If wires exceed the recommended distances, or if wires pass between buildings, give special consideration to
the effect of a lightning strike in your vicinity. The electromagnetic pulse caused by lightning or other
high-energy phenomena can easily couple enough energy into unshielded conductors to destroy electronic
devices. If you have had problems of this sort in the past, you may want to consult experts in electrical surge
suppression and shielding.
Asynchronous Terminal Connections
The RSP provides a console port to connect a terminal or computer for local console access. The port has an
RJ45 connector and supports RS-232 asynchronous data with distance recommendations specified in the IEEE
RS-232 standard.
Interference Considerations
When wires are run for any significant distance, there is a risk that stray signals will be induced on the wires
as interference. If interference signals are strong, they may cause data errors or damage to the equipment.
The following sections describe the sources of interference and how to minimize their effects on the Cisco
ASR 902 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 Cisco ASR 902 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.
For information about the electromagnetic compliance standards supported on the Cisco ASR 902 Router,
see the
Product Documentation and Compliance for the Cisco ASR 900 Series Aggregation Services Routers
document.
Cisco ASR 902 and ASR 902U Aggregation Services Router Hardware Installation Guide
55
Preparing for Installation
Site Cabling Guidelines
