Comtech EF Data LTT1450G - Manual (Page 32)

Serial Interface Protocol LTT1450G Ku-Band Loop Test Translator
Page 5-4 TM063 - Rev. 1
Alternately, a scalar network analyzer may be used for calibration. Calibration can be performed
manually (i.e. at every point for both bands) or the calibration can be computer automated with an ATE
setup.
Calibration can be performed on any one of the two active bands. Calibration is performed at precise 1
dB increments. The calibration sequence and associated commands are now presented.
5.4.1 Set-Calibrate-Mode Command
The set calibrate command is a key that allows entry into the calibration firmware shell. To enter
calibration mode enter the following command:
MMCAL{cr}
Once in calibrate mode the cal prompt, STATUS: BAND:{bb} ATT: {aa} CAL: >, will be sent where bb
and as represent the band and attenuation selected.
5.4.2 Valid Commands While in CAL Mode
When the unit is in CAL mode the following commands are valid:
U Coarse Increment DAC Value
u Fine Increment DAC Value
D Coarse Decrement DAC value.
d Fine Decrement DAC value
C Store DAC value at this location.
N Increment ATT location being calibrated while maintaining current DAC value.
P Decrement ATT location being calibrated while maintaining current DAC value.
X Exit CAL mode.
These commands do not require a carriage return, and all other commands are invalid. Any change of
the front panel switches will take the unit out of CAL mode. Both the increment and decrement DAC
value commands will wrap around when they reach full scale.