Comtech EF Data CDM-625A Installation And Operation Manual page 691

CDM-625A Advanced Satellite Modem
Appendix M
The Figure M-3 graph shows the switch points with the Target Eb/No margin set to 0dB.
However, the switch points can be moved (increased) by configuring the Target Eb/No margin
parameter, which can vary from 0 to 4.5 dB, in 0.5dB steps. In a fading environment, it is
strongly recommended to add sufficient margin to maintain an adequate link quality (and to
maintain demod lock) during the interval between the Eb/No degrading and the ACM controller
responding by lowering the ModCod. See Section M.11 Notes and Recommendations.
To continue with the configuration:
Step Task
6 (SELECT) CONFIG: IP  Switch-set-up  WAN
Enter the desired size of the WAN Buffer. The
minimum size is 20 milliseconds, and is referred to the
data rate corresponding to ModCod0. In order to
achieve minimum system latency, do not make this
value unnecessarily large. . Note that this does not
apply if the Packet Processor Card is installed.
Figure M-3. CDM-625A – ACM ModCod Switch Points
Front Panel Mnemonic
Ethernet Switch: Mode
MAC-Learning VLAN Qos Stats
M–11
MN-CDM625A
Revision 4
WAN PerPortCnfg
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