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CDD-880 Multi Receiver Router
Appendix D
D.1.2.2 CDM-840 ECM Message Processing
Figure D-3 illustrates the internal logic diagram of the remote processing registration message.
Processing
Description
Segment
1
ALOHA
2
REGISTRATION
3
SWITCH PENDING
4
SWITCHED
Figure D-3. ECM Message Processing – CDM-840 Remote Router
•
The CDM-840s are configured to receive the outbound carrier and are given a TAP (Group)
identifier number (default 1) that sets the internal filtering if multiple TAPs are used.
•
Upon receipt of the TAP message, the CDM-840 sets modem transmission parameters (if
required), initializes timing, and picks at random an SAS to start entry by sending a probe
(slot transmission).
•
The CDM-840, based on its current ECM state, either requests an assigned slot or waits to
be switched:
o An assigned slot request indicates to the HCC if the CDM-840 has more data (e.g.
registration protocol) to send.
o A switch request indicates that the CDM-840 is requesting dSCPC bandwidth. These two
flags are independent.
Remarks
Action
"Not Registered" or
"Reverted"
D–6
Remarks
A
Random attempts with backoff until in TAP
B
In TAP
C
Send Registration Protocol until complete
D
Not in TAP
Registration complete – no more Slots
E
needed
Received "Switch Command" message
F
from VMS
G
Received "Revert" message from VMS
MN-CDD880
Revision 2
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