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Connecting the Data Network Cables
Attenuation
The Cisco MC16C. Cisco MC16S, and MC28C line cards with the adapter card may require an attenuator in the downstream
configuration. The output is higher (+42 dBmV) and may overload the external upconverter input. Overdriving an external
upconverter may cause degraded bit error rate (BER), clipping and compression or distortion in the upconverter and possible
interference with adjacent channels.
Note Neither the Cisco uBR-MC16E cable interface line card nor the Cisco uBR10-MC5X20S/U/H needs additional
attenuation in the downstream path.
Upconverters
Table 4 lists the IF-to-RF upconverters that we recommend, and indicates whether a 10-dB attenuator is required.
Beginning with Cisco IOS Release 12.2(15)BC2, Cisco now supports IF muting with non-SNMP upconverters. In previous
releases, IF muting was not available for non-SNMP upconverters and this limited the availability of N+1 redundancy in some
circumstances. For additional information about IF muting and N+1 redundancy, refer to N+1 Redundancy for the Cisco Cable
Modem Termination System at the following URL:
http://www.cisco.com/univercd/cc/td/doc/product/cable/cab_rout/cmtsfg/ufgnpls1.htm
Cable Interface Line Card Cables
Equipment
• Dense Connector cable kit
• F connector cables
To cable the cable interface line card, follow these steps:
Step 1 Connect the upstream (US) cables to an RF switch or the other headend equipment.
Step 2 Connect the downstream (DS) cables to the IF-to-RF upconverter, if necessary. If you are using an attenuator, install it
on the upconverter F-connector before installing the cable.
Uplink Line Card Fiber-Optics Cables
Optical connectors are very sensitive to any dust particles or other contaminants. Cleaning the optical connections on the cables
and verifying the output power of the interface module helps to prevent damage to the fiber optics and system failure. To keep
the connections as clean and contaminant-free as possible, always clean fiber-optic connections before installing the cables and
always use protective caps on the connectors that are not cabled. For cleaning information see Inspection and Cleaning
Procedures for Fiber-Optic Connections at the following URL: http://www.cisco.com/warp/public/127/cleanfiber2.html
Tip Inspect and clean the bulkhead connection first, and then inspect and clean the fiber cable just before you install it into
the bulkhead connector.
Table 4 Recommended IF-to-RF Upconverters
IF-to-RF Upconverter Need 10-dB Attenuator? URL
Motorola/General Instrument C6U, C8U
Yes http://www.gi.com
Vecima MA4040B, Vecima HD4040
Yes http://www.vecima.com
Scientific Atlanta Continuum 9860, 9861
No http://www.scientificatlanta.com