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Using the Equipment
3.11.5.5
Functional Description
RAS is an Ericsson proprietary scrambling or Conditional Access system used to
prevent unauthorized reception of transmissions. These transmissions are not
normally Direct to Home (DTH); but will more likely be broadcasters sending signals
for Contribution and Distribution purposes.
3.11.5.5.1
RAS Types
There are two types of RAS numbered 1 and 2.
Note: Currently the RX8000 only supports RAS1.
3.11.5.5.2
RAS1
RAS1 uses a 28-bit key. Of the 268,435 and 456 possible keys, half are reserved for
installations which are not DSNG based (Fixed Link Systems) and the other half for
installations which are DSNG-based.
3.11.5.5.2.1
Fixed Link Systems
Each separate system has a single unique key allocated and installed by Ericsson
AB. The broadcaster/owner of the transmission system is not allowed to adjust or
change the key in any way.
RAS1 requires that the Multiplexer has a RAS cypher module and an allocated
RAS1 fixed key installed. The IRD must have the same RAS1 fixed key entered by
Ericsson Support Engineers or the manufacturing site using a unit customization
tool.
3.11.5.5.2.2
DSNG Systems
The Ericsson DSNG includes RAS1 scrambling as standard. The operator is
allowed to input a RAS1 key within the reserved range. In order to receive and
descramble a RAS1 transmission from a DSNG, the IRD must be in DSNG Key
mode and possess the matching key to allow descrambling.
3.11.5.6
RAS Mode Configuration
Figure 3.75 DSNG Key Field
3-160
•
RAS1 uses a fixed key which is installed when the equipment is
commissioned.
•
RAS2 uses a variable key which is changed at frequent intervals by software
from a PC located at the site at the head-end. This PC is under the control of
the broadcaster.
EN/LZT 790 0005 R7A
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