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PSM-500/500L/500LT SCPC Satellite Modem
3.5.1 Power-Up
On initial and every subsequent power-up, the modem microprocessor will test itself and several
of its components before beginning its main monitor/control program. These power-up
diagnostics show no results if successful. If a serious power on failure is detected, the ALARM
LED is flashed at an approximate 4 Hz rate. Other failure modes are displayed on the front panel
LCD.
New modems from the factory have default values placed into the EEPROM for operating
parameters. If a Monitor/Control System does not configure the modem automatically via the
serial command channel, the modem can be easily configured from the front panel or can be
connected to a VT100 protocol terminal to set the modem's operating parameters. To restore the
default parameters the modem can be powered on while depressing the "Clear" key.
The most common default parameters placed into the EEPROM are as follows: A modem can be
returned to the factory default settings by using the front panel command <Unit: Config -
Recall>, then editing (or quick edit) and choosing the "Factory" or "0" selection option.
Modulator:
Carrier Frequency = 70.00 MHz
Data Rate = 256 kbps
Modulation = QPSK
Code Rate = Rate 1/2
Differential Encoder = Enabled
Scrambler = Auto
Clock phase = Normal
Data = Normal
Clock Source = Internal
RTS = Ignore
Carrier = Off.
All Mod Alarms to Relay A
Modem Unit:
Modem Reference: Internal, 10 MHz
Remote Port Address = 1
Remote Port = RS-232
Remote Mode = Binary Packet
Remote Rate = 9.6 kbps
Remote Data Format = 8 data bits, 1
stop, no parity
In a properly operating system, with an incoming carrier available for the demodulator, the
modem's Alarm (red) and Warning (yellow) LEDs should all go out. Without an acceptable
incoming carrier the Demod "Major Alarm" and "Summary Alarm" will illuminate. When the
incoming carrier is acquired, the green "Signal Lock" LED should illuminate. The "Transmit On"
LED will also illuminate if the transmit output is enabled.
3.6 L-Band Feature Operation
Note: The following special L-Band features refer to the transmit and receive for the PSM-
500L and the PSM-500LT .
PSM-500/500L/500LT - Rev. 0.91
Demodulator:
Carrier Frequency = 70.00 MHz
Data Rate = 256 kbps
Modulation = QPSK
Code Rate = Rate 1/2
Differential Decoder = Enabled
Descrambler = Auto
Clock phase = Normal
Data = Normal
Clock Source = Receive
Sweep mode = Fast
Acquisition Range = +/- 30 kHz
All Demod Alarms to Relay B
Interface:
Mode = RS-449
All Tests Off
Data and Clocks in normal mode (not
inverted). The XMT Clock now uses a
default "Auto" mode that detects the
proper phasing and applies it.
Operation
Page 3-31
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