Comtech EF Data SDM-2020 - Manual (Page 197)

SDM-2020 Satellite Demodulator Revision 4
ASI/LVDS Data Interface MN/SDM2020D.IOM
13–7
13.1.4 Loopback Connection
Refer to Table 13-3 for additional requirements for Loopback.
Table 13-3. Loopback Connections
ASI Interface is active in Modulator Loops ASI input, J3 (or J4), to ASI output, J7. If JP1 is
Off, then J3 (J4) also loops to J6, the LVDS-DVB parallel
output
The LVDS signal contains D0-D7, Sync, Dvalid, and Clock
LVDS Interface is active in
Modulator If J1 is On, then J6 (LVDS-DVB input) is looped to the
ASI output J7.
ASI Interface is active in
Demodulator JP1 is Off (Normal): When Loopback is engaged the TX
ASI (J3) input connects simultaneously to the RX ASI
(J7) and to the RX LVDS connector (J6). The LVDS
signal contains D0-D7, Sync, Dvalid, and Clock
JP1 is On: When Loopback is engaged the TX LVDS
(J6) input connects to the RX ASI (J7) connector.
LVDS Interface is active (output) in
Demodulator JP1 is ON: When Loopback is engaged the TX LVDS
(J6) input connects to the RX ASI connector (J7). The
LVDS signal contains D0-D7, Sync, Dvalid, and Clock.
JP1 is OFF (Normal): When Loopback is engaged the TX
ASI input connects to the RX ASI connector and to the
RX LVDS connector. The LVDS signal contains D0-D7,
Sync, Dvalid, and Clock.
13.1.5 Loop Thru
The operation of Loop Thru is the same as Loopback except the normal operating mode
not a test mode, and the TEST LED does not illuminate.