2-15
Cisco ASR-920-24SZ-IM, ASR-920-24SZ-M, ASR-920-24TZ-M Aggregation Services Router Hardware Installation Guide
Chapter 2 Preparing for Installation
Site Planning
Asynchronous Terminal Connections
The Cisco ASR 920-24SZ-IM, ASR-920-24SZ-M, ASR-920-24TZ-M Router provides a console port to
connect a terminal or computer for local console access. The port has an RJ-45 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 920-24SZ-IM, ASR-920-24SZ-M, ASR-920-24TZ-M 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 920-24SZ-IM,
ASR-920-24SZ-M, ASR-920-24TZ-M 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 electrode magnetic compliance standards supported on the Cisco ASR
920-24SZ-IM, ASR-920-24SZ-M, ASR-920-24TZ-M Router, see the Regulatory Compliance and
Safety Information for the Cisco ASR 920 Series Router document.
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 Cisco ASR
920-24SZ-IM, ASR-920-24SZ-M, ASR-920-24TZ-M 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 Cisco ASR
920-24SZ-IM, ASR-920-24SZ-M, ASR-920-24TZ-M Router operating environment.
To Next Page
Loading...
Need help?
General
