Configuring The Dmd20 For Drop And Insert; Data Rate - Radyne DMD20 Installation And Operation Manual

DMD20 Universal Satellite Modem
Case 4: Loop Timing Example
Method 1 -
Set mode to IBS
Under Interface menu:
Under Tx Setup menu:
Method 2 -
Set mode to Closed Net
Under Interface menu:
Under Tx Setup menu:

4.6 Configuring the DMD20 for Drop and Insert

Several dependencies exist when configuring the modem for Drop and Insert (D&I). The
following paragraphs explain these dependencies and provide the user with the information
required to ensure smooth transition into D&I and to minimize the potential impact of these
dependencies.

4.6.1 Data Rate

Data Rate affects the Drop and Insert function in the following ways:
•
It determines the number of Satellite Channels that will be displayed in the Edit Maps.
•
It contributes to the Operational Mode selection process. Trying to change the
Operational Mode to D&I when a data rate is not set to a valid D&I rate will result in
the error message 'INVALID DATA RATE,' and the mode change will not be allowed.
•
It contributes to the Terrestrial Framing Mode selection process. Trying to select a
T1-type Drop Mode such as T1-ESF with the mod data rate set to 1920000 bps (a
valid E1 D&I rate but not a valid T1 rate) will result in the error message 'INVALID
DROP MODE' and the selection will not be allowed. Trying to select a T1 type Insert
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.
TM103 – Rev. 1.1
Set INTF to RS-422
Set SCT Source to SCR
Set Tx Clock to SCTE
Set INTF to RS-422
Set SCT Source to SCR
Set Tx Clock to SCTE
User Interfaces
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