Cisco 7246 Hardware Installation Guide - Page 35

Chapter 1 Cisco uBR7200 Series Overview Hardware Component Descriptions Tip If you order an I/O controller as a spare for a Cisco uBR7200 series, use the product numbers UBR7200-I/O= (without a Fast Ethernet port) or UBR7200-I/O-FE= (with a Fast Ethernet port). These I/O controllers have the Cisco IOS software images used by the Cisco uBR7200 series loaded on the flash memory SIMMs. Cisco Cable Interface Line Cards Cisco cable interface line cards (also known as line cards), together with external IF-to-RF upconverters, serve as the RF interface between the cable headend and both DOCSIS-based cable modems and EuroDOCSIS-based cable modems and set-top boxes (STBs). Cisco cable interface line cards separate downstream output and upstream input cable interfaces on the Cisco uBR7200 series universal broadband router to enable downstream and upstream signal combining and splitting arrangements. Cisco cable interface line cards can be used in both 6-MHz NTSC standard and 8-MHz PAL/SECAM channel environments. The cable interface cards connect directly to the universal broadband router's midplane. Cable interface line cards installed in the Cisco uBR7200 series router support OIR. The downstream ports must be connected to external IF-to-RF upconverter hardware. Caution To ensure the proper flow of cooling air across internal components, make sure that blank cable interface line cards, blank port adapters, and blank cable clock cards are installed in unoccupied chassis slots. Also make sure that power supply filler plates (with their attached air dams) are installed in unoccupied power supply bays. For more information regarding specific cable interface line cards, refer to the Cisco uBR7200 Series Cable Interface Line Card Hardware Installation Guide. To view the document online, go to the following URL: http://www.cisco.com/en/US/docs/interfaces_modules/cable/line_cards/installation/guide/mcxxfru.htm l Cisco Cable Clock Card (Cisco uBR7246VXR Only) The cable clock card works only with the Cisco MC16S or Cisco MC16E cable interface line cards and the Cisco uBR7246VXR router. The cable modem must also support the clocking mode. The Cisco cable clock card is a dual-port field-replaceable component that is designed to provide a reliable national clock signal to the Cisco uBR7246VXR. The primary and secondary DB-15 interfaces on the front of the cable clock card connect to external T1 clock signal sources. When installed in the Cisco uBR7246VXR chassis, the cable clock card can propagate a national clock signal throughout the router's midplane by locking onto an external T1 signal originating over the PSTN, by locking onto a T1 clock signal originating from a port adapter installed in the same chassis, or by connecting to a Global Positioning System (GPS) receiver generating a T1 clock signal. The cable clock card does not support OIR. Caution To ensure adequate airflow across the router's components, a cable clock card or a blank cable clock card cover plate must be installed in the cable clock card slot on the Cisco uBR7246VXR. OL-5421-03 Cisco uBR7200 Series Universal Broadband Router Hardware Installation Guide 1-17