DMD2401/DMD2401L/DMD2401 IBS/IDR Satellite Modem
Operation
TM065 - Rev. 3.3
3-3
3.3 DMD2401 Initial Configuration Check
The DMD2401 is shipped from the factory with preset factory defaults. Upon initial power-up, a
user check should be performed to verify the shipped modem configuration. Refer to Section 3,
Operation for the Modulator and Demodulator Front Panel Menu Screens to locate and verify the
following configuration settings are correct:
Note: Transmit (Tx) and Receive (Rx) Interface types are dependent upon the customer’s
order.
Standard DMD2401 Factory Configuration Settings
Modulator:
Data Rate:
2,048,000 Kbps
Forward Error Correction:
1/2 Rate Viterbi
Modulation:
QPSK
Frequency:
70.000000 MHz
950.000000 MHz (L-Band Option)
Modulator Output Power:
-30 dBm
Carrier:
Off
Demodulator:
Data Rate:
2,048,000 Kbps
Forward Error Correction:
1/2 Rate Viterbi
Frequency:
70.000000 MHz
950.000000 MHz (L-Band Option)
To lock up the modem, turn the carrier ON, enter ‘IF Loopback Enable,’ or connect a loopback
cable from J1 to J4 on the rear panel of the modem.
3.4 DMD2401 Automatic Uplink Power Control (AUPC Operation)
The DMD2401 modem has an optional built-in provision for Automatic Uplink Power Control
(AUPC). AUPC attempts to maintain a constant E
b
/N
o
at the receive end of an SCPC link. This is
especially useful when operating over a satellite at Ku-Band frequencies in locations with high
rainfall periods.
Note: An Asynchronous or IBS Interface is required for AUPC. Also, IBS (Async Framing
Mode MUST be selected to provide a channel for AUPC operation.
The IBS (Async Framer Data Mode provides a service channel between the two sites of a link
permitting the modem processors to send messages and get responses over this channel. AUPC
can be set to operate on either or both directions of a link but always requires a bi-directional
channel. Therefore, both the Modulator and Demodulator interface mode must be set to IBS
(Async for the AUPC menus to be visible and for the AUPC function to operate properly. The
AUPC functions and their descriptions are shown below:
The AUPC menus are located under the Modulator Menu as shown in Section 4.
Summary of Contents for ComStream DMD2401
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