Comtech EF Data CDM-760, Installation And Operation Manual

Page: 112 / 441

Front Panel Operation Revision 4
CDM-760 Advanced High-Speed Trunking Modem MN-CDM760
6–23
1) If you are in MultiStream Mode, the buffer depth is calculated using only the
Ethernet data rate – not the aggregate data rate.
2) The WAN Buffer is a FIFO (First In First Out) buffer, not a circular buffer. This
means that, as long as the Ethernet ingress to the modem does not exceed the
Ethernet Data Rate of the modem, the buffer will always remain relatively empty
and there will be NO ADDED LATENCY. The buffer will begin to fill and you will
experience added latency only when the Ethernet traffic ingress to the modem
exceeds the egress of the Ethernet data rate.
3) By enabling Flow Control, the modem begins to send Pause Frames to any device
connected to the Ethernet Data Interfaces at approximately 87% capacity. Pause
Frames cease to be sent to the Ethernet Interfaces when the WAN Buffer Full
Status drops below 75% capacity. See (CONFIG: INTF)(GBEIX)

FlowControl in
Section 6.2.2.4.2 for more information about Flow Control.
6.2.2.3 (CONFIG:) Rx
Rx: Mod Data Freq EsNo
Data 155520.000kbps 060140.976ksps (

)
On the top line – Use the   arrow keys to select a parameter. Press ENTER .
The
read-only
bottom line shows the operating data rate (in kbps) and symbol rate (in ksps).
The Data rate displays “00000.000kbps” when the demodulator is unlocked.
6.2.2.3.1 (CONFIG: Rx) Mod
This screen displays “Demodulator Is Not Locked” if the demodulator is unlocked.
ModCod=8PSK 8/9 Frame:Normal
Pilots:On (

)
This
read-only
screen identifies the active modulation type, coding, Framing Mode, and Pilot
setting.
ModCods and coding are valid for the listed network specifications as follows:
Network Spec QPSK 8PSK 16APSK 32APSK 64APSK
DVB-S2
1/2, 3/5, 3/4, 4/5,
5/6, 8/9, 9/10
3/5, 2/3, 3/4, 5/6,
8/9, 9/10
2/3, 3/4, 4/5, 5/6,
8/9, 9/10
3/4, 4/5, 5/6, 8/9,
9/10
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