Comtech EF Data CDM-750 Installation And Operation Manual page 290

CDM-750 Advanced High-Speed Trunking Modem
Appendix G
•
The arrows in the diagram indicate the direction of data flow; while data flow between
Blocks 1 and 2 is valid, data flow between Blocks 2 and 1 does not occur. Arrows on both
ends of a link show where data flow is bidirectional.
Name
LAN Region
Block 1 – Ethernet Switch
Block 2 – Terrestrial Port
Processor (Tx)
Block 3 – Expansion Slot
Block 4 – Terrestrial Port
Processor (Rx)
Block 5 – Deframer
Block 6 – Framer
Block 7 – Modulator
Block 8 – CnC
Block 9 – Demodulator
Block 10 – µP / M&C /
Management
IF Region
Function
This unmarked region of the diagram refers to the LAN – the source / destination for data traffic.
The information of interest is tailored to Ethernet interfaces, so most of the statistics do not apply
to the G.703 interface.
The LAN's access to the modem is at the Ethernet switch. There are two RJ-45
10/100/1000BaseT ports and one optional optical Gigabit Ethernet (SFP module) port available
at the rear of the modem.
Data from the LAN destined to the satellite flows into this block.
This is reserved for future plug-in modules.
This is the counterpart to the Tx processor. It forms Ethernet packets and forwards them to the
Ethernet Switch.
The data from the satellite frames is recovered.
Data processing to assemble data into frames for the modulator is performed in this block.
Frames are mapped into the appropriate FECFrame and mapped into the selected ModCod for
transmission to the satellite.
Signals to and from the satellite are processed here to cancel the locally transmitted carrier and
receive the carrier from the distant end.
Carriers received from the satellite are processed here to recover data frames.
The microcontroller (µP) is involved in collection and calculation of statistics.
This unmarked region of the diagram refers to data to or from the satellite link.
Figure G-1. CDM-750 Data Flow Diagram
G–2
Revision 2
MN-CDM750