Cisco Model 6109 6 MHz Off-Air Reference (NTSC) Guía De Instalación
78-4021139-01 Rev D
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A
access network
An HFC network in a DBDS consisting of two elements: (1) fiber optic transmission systems
that extend from a hub to the HFC nodes and (2) a coaxial bus network extending from the
HFC nodes to the DHCTs at the end of the Access Network. The HFC network sends analog
signals. QAM modulators allow digital signals to be carried on this analog medium.
application server
App Server or SARA Server. A server that executes applications that are required to provide
digital services to subscribers. The Applications Server comes with the following set of
standard applications:
- Virtual Channel Server (VCS)
- Interactive Program Guide (IPG)
- DHCT Configuration
- Pay-Per-View (PPV) event and service setup
- Emergency Alert System (EAS) messaging
The Application Server uses multi-mode fiber to transfer data through the ATM switch to the
DNCS or router. Data is sent in ATM cells over permanent virtual circuits (PVCs).
B
BW
bandwidth. A measure of the information-carrying capacity of a communications channel, for
example the range of usable frequencies that can be carried by a CATV system. The
bandwidth corresponds to the difference between the lowest and highest frequency that can
be carried by the channel.
C
CA
conditional access. The system, software, and components necessary to provide or deny
subscribers selective access to specific services.
carousel
A logical element that carries information from a BFS server to DHCTs that request the
information. The carousel makes the information available to all DHCTs in the system.
However, only those DHCTs specifically authorized and looking for the information will
receive it. Carousels are sometimes referred to as sources or data pumps.
Glossary