Comtech EF Data DMD2401/DMD2401L - Manual (Page 33)

Operation DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem
3-10 TM065 – Rev. 3.3
Number of
Slots (n)
D&I Data Rates
1 64,000
2 128,000
3 192,000
4 256,000
5 320,000
6 384,000
8 512,000
10 640,000
12 768,000
15 960,000
16 1,024,000
20 1,280,000
24 1,536,000
30 1,920,000 (valid with
E1 Interface only)
3.10.4 Terrestrial Framing - Drop Mode/Insert Mode
The Drop Mode selection and the Insert Mode selection identify the terrestrial data-framing
format. As previously mentioned, their selection is influenced by the mod and demod interface
types. In turn, the selection of the terrestrial framing formats influences the satellite channel to
terrestrial timeslot mappings in the following manner:
1.
The selection of T1-D4, T1-ESF, or T1-D4-S, or T1-ESF-S type terrestrial framing format
limits the terrestrial timeslots to values from 1-24.
2.
The selection of PCM-30 or PCM-30C type terrestrial framing limits the terrestrial
timeslots to values from 1-15, 17-31. In these modes, terrestrial timeslot 16 is reserved
for ABCD signaling and may not be dropped or inserted.
3.
The selection of PCM-31 or PCM-31C type terrestrial framing limits the terrestrial
timeslots to values from 1-31.
Therefore, the terrestrial framing format should be identified via the Drop Mode and Insert Mode
entries prior to editing the Drop or Insert satellite channel to terrestrial timeslot maps.
3.10.4.1 Insert Terrestrial Frame Source
The insert terrestrial frame source selection tells the modem where the insert terrestrial frame is
coming from. External means the terrestrial frame is to be input via the Insert Data In port.
Internal means that the modem needs to generate the terrestrial frame and that all non-inserted
timeslots need to be filled with the appropriate idle code based upon the terrestrial framing (T1 or
E1). In addition, the selection of the insert terrestrial frame source also influences the Buffer
Clock selection in the following manner: