Comtech EF Data SDM-300A, Installation And Operation Manual

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Operation SDM-300A Satellite Modem
3–82 Rev. 4
Table 3-9. EFD Closed Network Parameter Settings
Parameter Front Panel Setting Reference Menu
Modem Type EFD Utility Modem Type
TX Data/Code Rate TX-V, QPSK 1/2 Configuration Modulator
TX-IF Output ON Configuration Modulator
RX Data/Code Rate RX-V, QPSK 1/2 Configuration Demodulator
TX Clock Source TX Terrestrial Configuration Interface
Buffer Clock Source Satellite Clock Configuration Interface
Modulator Type EFD Closed (All modulator types are
accessible) Utility Modulator
Encoder Type Viterbi or Sequential Utility Modulator
Demodulator type EFD Closed (All modulator types are
accessible) Utility Demodulator
Decoder Type Viterbi or Sequential Utility Demodulator
TX Overhead Type None Utility Interface
RX Overhead Type None Utility Interface
Interface Type EIA-422, EIA-232, V.35, G.703
(see
Note)
Utility Interface
Buffer Program Bits or Milliseconds Utility Interface
RTS TX-IF Cntrl OFF or ON Utility Interface
CTS Delay 0 Seconds Utility Interface
Note: To use G.703, the modem must have the required G.703 Overhead board (PL/5305-1)
installed.
3.4.2.6 Custom Operation
Note: If the modem serves as the backup unit for a rack of modems having different
hardware and FAST options, then the backup modem shall have all of the features and
hardware found in the other modems.
Operating in Custom mode allows access to all front panels menus, including the Utility
menus. The Custom operation mode is manly used when the modem must function with
no overhead in an open network application. For example, to use the modem in the IDR
mode of operation with overhead (308-2), the following steps are taken:
1. Select the IDR modem type, so that the modem loads the IDR default parameter.
2. Select the Custom modem type, which allows Access to the modulator and
demodulator overhead type.
3. Select NONE for the overhead types.
A protection switch can make use of the Custom operation mode when the modem is
configured as a backup modem. Because the backup modem is operating in Custom
Mode, the switch can program all the backup modem parameters. Thus, the one backup
modem can be made compatible with all of the various application types found in the
rack.