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Appendix H
Mode such as T1-D4 with the demod data rate set to 1920000 bps will result in the
error message INVALID INSERT MODE and the selection will not be allowed.
•
Once D&I Mode has been selected, trying to change the data rate to something other
than another valid D&I data rate will result in the error message 'RATE OUT OF
BOUNDS' and the change will not be allowed.
•
Once D&I Mode has been selected with a T1 Terrestrial Framing Mode, attempting to
change the data rate to 1920000 will result in the error message 'RATE OUT OF
BOUNDS' and the change will not be allowed.
Therefore, the data rate should be entered as the first step in configuring the modem for D&I.
The Mod Data Rate should be set according to the number of timeslots to be dropped and the
Demod Data Rate should be set according to the number of timeslots to be inserted. The
following table gives the allowable D&I data rates based on the number of slots (n) to be dropped
or inserted.
n = 1, data rate = 64000
n = 2, data rate = 128000
n = 3, data rate = 192000
n = 4, data rate = 256000
n = 5, data rate = 320000
n = 6, data rate = 384000
n = 8, data rate = 512000
n = 10, data rate = 640000
n = 12, data rate = 768000
n = 15, data rate = 960000
n = 16, data rate = 1024000
n = 20, data rate = 1280000
n = 24, data rate = 1536000
n = 30, data rate = 1920000 (valid with E1 Interface only)
H.1.2 Operational Network Specification
The Network Specification of the Modem often determines which additional menus and displays
are available for use by the operator. The D&I Mode-specific menus will not be displayed unless
the Network Specification of the modem is set to D&I. Therefore, the second step in configuring
the modem should be to set the Network Specification to D&I. At this point, the D&I specific
menus in the Interface section will become available and will remain available until the Network
Specification of the modem is changed to something other than D&I.
When the Network Specification is changed to something other than D&I, the D&I specific menus
will automatically disappear.
H.1.3 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 Modulator and Demodulator
Data Rates, and trying to select a T1 Type Framing Format with a data rate of 1920000 bps will
result in an error message. In turn, the selection of the terrestrial framing formats influences the
satellite channel to terrestrial timeslot mappings in the following manner:
The selection of T1-D4, T1-ESF, or SLC-96 type terrestrial framing format limits the
terrestrial timeslots to values from 1 - 24.
H-10
DMD50 Universal Satellite Modem
TM118 – Rev. 1.1
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