Overview - Motorola OM 2000 Installation & Operation Manual

2 OVERVIEW

The Motorola OM 2000 creates a QPSK-modulated signal to carry the out-of-band
(OOB) datastream of a digital CATV system from the headend to set-top devices
(STDs) installed in subscribers' homes. The OOB datastream is the control link
through which the headend transmits the commands and authorization messages
that control the STDs distributed throughout the CATV system. The headend can
also use the OOB datastream to deliver other types of information, including:
•
Electronic Program Guide (EPG) information
•
Application code downloads
•
Control messages for emergency situations
•
Data services
•
Executable code downloads to fix or upgrade cable terminal operation
Other devices in the headend create the specific commands, messages, and
downloadable code that make up the information contained in the OOB datastream.
The OM 2000 accepts this information and processes it for delivery on the OOB
channel by combining it into an MPEG-2-compliant transport multiplex and outputting
that transport multiplex as an RF signal. Other output formats are also available to
support specific application requirements.
Figure 2-1 illustrates the operational flow through the OM 2000:
Figure 2-1 — OM 2000 operational flow diagram
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