Drop Only; Insert Only - Radyne DMD20 Installation And Operation Manual

DMD20/DMD20 LBST Universal Satellite Modem Theory of Operation

3.10.1 Drop Only

When Drop is enabled and Insert is disabled, the DMD20 performs a drop-only function. Framed
E1 or T1 Data is input via the Send Data In Port, the selected timeslots are dropped into the IBS
frame structure, and the unaltered terrestrial data is output via the Send Data Out Port (refer to
Figure 3-12).
Figure 3-12. Drop Only

3.10.2 Insert Only

When Insert is enabled and Drop is disabled, the DMD20 performs an insert-only function. If
framed terrestrial E1 or T1 Data is available, it should be input via the Insert Data In Port. The
Terrestrial Data is buffered inside the Modem. The RX Baseband Processor inserts satellite data
into the selected timeslots in the G.704 Frame and the modified terrestrial data is then output via
the Receive Data Out Port (refer to Figure 3-13).
If framed terrestrial data is not available, selection of the Internal T1/E1 frame source will cause
the modem to generate the required G.704 Frame. The Satellite Data will be inserted into the
selected timeslots, and the resulting terrestrial data will be output via the Receive Data Out Port.
Any non-inserted timeslots in the G.704 Frame will be filled with the appropriate Idle Code (refer
to Figure 3-14).
Figure 3-13. Insert Only with Eternal Frame Source
TM103 – Rev. 2.5 3-15