Cisco Headend System Release 2.5 User Guide
1-4
Overlay Technology
4004831 Rev B
Differences Between a DBDS and an Overlay Environment,
Continued
Typical Overlay Environment Set Ups
The specific equipment configuration required to provide the clear and encrypted
inputs to the GoQAM is highly variable and depends upon the specific hardware
configuration of the incumbent CA system onto which Overlay technology will be
deployed. Following are two examples that illustrate commonly used connections
when Overlay technology is deployed alongside a non-Cisco headend.
Overlay Environment Without a Multiplexor With an IRT
In an Overlay environment without a multiplexor (MUX), the Integrated Receiver
Overlay Environment Without a Multiplexor With an IRT
In an Overlay environment without a multiplexor (MUX), the Integrated Receiver
Transcoder (IRT) does the encryption for the non-Cisco set-tops.
The following graphic illustrates how Overlay technology interfaces to a non-Cisco
The following graphic illustrates how Overlay technology interfaces to a non-Cisco
headend that uses a simple IRT. The IRT performs a number of functions including
Mediacipher encryption. With an IRT, clear and encrypted signals are available
through DHEI connectors on the IRT back panel.