Distance Limitations - Cisco uBR924 Installation Manual
Cable access router
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Also See for uBR924:
- Troubleshooting tips (74 pages) ,
- Installation and startup (34 pages) ,
- Configuration manual (52 pages)
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Chapter 2
Preparing for Installation
Check the cables for general quality level, tears or cuts in the insulation, insulation that is at least 80%
braid with foil, a broken or bent center conductor at the conductor ends, the length of the center
conductor, and splitters or amplifiers that have been added to extend video connectivity at the
installation site.
The center conductor should extend 1/8 inch (3.2 mm) beyond the end of the conductor.
Note
Tips
Cisco recommends that you replace any cable that is in question and begin the installation
with clean, two-way digital data transmission media. If the cable is of high-quality and
was recently installed, replacing the connectors with high-quality connectors can also
improve performance and eliminate future service calls.
Caution
If you replace a connector, be careful not to score the center conductor. A scored conductor
can reduce or impair performance for channels broadcast between 550 and 860 MHz. If
the center conductor is too short, signals between 5 and 42 MHz might be affected.
Distance Limitations
The size of your networks and the distances between connections on the CATV network can affect the
successful installation of a Cisco uBR924 router, which must be within 100 miles of the CMTS. This
distance can also be defined in relation to the speed of light through the transmission network as being
less than 2 msec from the CMTS to the Cisco uBR924 router and back again.
Note
Exceeding this distance is a violation of the DOCSIS RFI specification.
When preparing a site for network connections to the Cisco uBR924 router, consider the following:
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Potential distance limitation problems in the CATV network can be reduced by ensuring the following
factors:
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OL-0338-01 (3/2000)
The number of amplifiers from the installation site to the nearest node
The number of outlets and amplifiers at the installation site
Cable pinouts if you plan to build your cables
A correct, linear unity gain two-way sweep procedure is in place
Industry-standard configuration practices are used at the headend
The downstream frequency is known at the time of installation
The absolute downstream signal level can be measured where it enters the cable access router
Cisco uBR924 Router Hardware Installation Guide
Site Requirements
2-7
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Table of Contents
Troubleshooting
