Internal Clock; Loopback Features (Terrestrial & If) - Comtech EF Data DMD1050TS Installation And Operation Manual

3.8

Internal Clock

The time and date are used to time-stamp system events. You can change the time and date via
the Web Browser.
3.9 Loopback Features (Terrestrial & IF)
CAUTION: DATA LOSS POSSIBLE
To run any type of data test with an Ethernet interface, you must use two
modems connected back-to-back. Using the modem's loopback with the
Ethernet data interface causes unwanted network loops and useless results.
The modem allows for several different loopbacks:
•
IF Loopback – Tx IF port is looped back to the Rx IF port
•
Tx Terrestrial Loopback - Tx Data port is looped back to the Rx Data port after the
interface driver/receiver (prior to the framing unit)
•
Tx Baseband Loopback - Tx Data port is looped back to the Rx Data port after the
interface driver/receiver (after the framing unit)
•
Rx Terrestrial Loopback - Receive Data from the satellite is looped back for
retransmission to the satellite, providing a far end loopback (prior to the framing unit)
•
Rx Baseband Loopback - Receive Data from the satellite is looped back for
retransmission to the satellite, providing a far end loopback (after the framing unit)
•
Tx/Rx Terrestrial Loopback - provides both Terrestrial loopbacks simultaneously
•
Tx/Rx Baseband Loopback - provides both Baseband loopbacks simultaneously
See Figure 3-7 through Figure 3-9 for loopback functional block diagrams.
Theory of Operation
DMD1050TS Satellite Modem Board
3–17
Revision 1
MN-DMD1050TS