Comtech EF Data CST-5000 - Manual (Page 93)

Theory of Operation CST-5000 C-Band Satellite Terminal
5–4 Rev. 9
5.1.2.1 Remote Interface Specification
Refer to Appendix B for information on remote control operation.
5.1.3 Terminal Default Conditions
On initial power-up, the unit will default to the following parameters:
Parameter Default
Baud Rate 9600
Parity Even
Device Address
1
U/C Gain Minimum
D/C Gain Minimum
RF Output OFF
U/C Frequency 6135.00 MHz
D/C Frequency 3925.00 MHz
5.1.4 Theory of Operation
Refer to Figure 5-3 for a functional block diagram of the M&C.
The M&C board performs the following operations:
• Receives the desired frequency from either the remote EIA-232/485 or local
keypad, and after converting it to a synthesizer setting, stores it to the applicable
synthesizer output latch.
• Reads the thermistors located in the up converter, down converter, and HPA, and
converts the signals into temperatures for display.
• Reads the characterization EEPROMs in the up converter, down converter, and
HPA, and calculates an Automatic Gain Control (AGC) voltage based on
frequency and temperature to linearize the respective module.
• Turns the fan on or off, depending on the temperature.
• Receives fault inputs from all modules, and presents them to the remote
EIA-232/485 and the optional local keypad display.
• Performs an initial current sense on the LNA, and stores the reading in the
EEPROM. Subsequent current sense readings are taken and compared to the
initial reading to determine a fault.