DACS App Note

DACS DRED (Daily Readiness Test) Update (#5)

Testing the TDM and Remote Interface Units:

When to do it:
  1. You suspect you have a faulty RIU.
  2. You want to check the operation of your TDM ring.
  3. You want to check the headset audio quality.
What it checks:
  1. Audio from the DACS to the RIU by sending a unique tone/signal to each RIU channel.
  2. Headset audio by looping back RIU audio inputs to the corresponding RIU audio outputs.
  3. Digital inputs and outputs.
  4. The integrity of the TDM ring.
How to launch it:
  1. From the Model Builder main menu select "Quit".
  2. Type dred_riu at the DOS prompt and press ENTER.
  3. You will be prompted to choose the TDM and RIU you wish to test.
  4. Valid choices are TDM 1 or 2 and RIUs 1 - 6.
    1. Only 1 RIU is tested at a time.
    2. To test additional RIUs re-launch dred_riu and select the other RIU(s) you wish to test.

NOTE: If audio starts blaring from your headset or speakers press the F3 key to "freeze" the DACS. Turn down the volume of those devices and then press F3 again to "unfreeze" the DACS.

Checking the audio outputs:
  1. A unique audio signal is sent to each RIU channel
    1. CH A = Caution tone
    2. CH B = Sine wave sweep
    3. CH C = Jamming noises
    4. CH D = ATIS message
  2. Check that the tones are audible and free from distortion, breakup and noise.
Enabling the audio loopback:
  1. From the main menu select "Models" and choose "Model 1" or "Model 2" depending on the selection you made when you started dred_riu.
  2. Press F2 and choose "Controls".
  3. The "Output_Control" object should be highlighted. Press ENTER to access this object.
  4. Use the arrow keys to move to the "Local X" field.
  5. Use the +/- keys to toggle this field from ON to OFF.
    1. The automatic tones will cease.
  6. Speak into the microphone and listen for the audio to be looped back to the headset or speaker.
    1. CH A input is looped back to CH A output and so on for each RIU channel.
Testing the digital inputs and outputs:
  1. Triggering the digital input (DI) for a given channel will trigger the corresponding digital output (DO).
  2. You can measure the state of the digital out (if used) by connecting an ohmmeter across pins 1 and 6 of the RIU DB-9 connector.
    1. The resistance will change from high to low as the DO is activated.
  3. If the DO is not used the state of the DI may be viewed in the model.
  4. From the main menu select "Models" and choose "Model 1" or "Model 2" depending on the selection you made when you started dred_riu.
  5. Press F2 and choose "Controls".
  6. Use the arrow keys to move down through the controls list until RIU_x_IN_A/B/C/D objects appear.
    1. "x" refers to the RIU under test.
  7. Toggle the DI and watch the state in the model change from 0.0 to 1.00000.
Restoring the DACS to normal operation:
  1. From the Model Builder main menu select "Quit".
  2. You are now at the c:\mbuilder\user\riutest prompt.
  3. Navigate back to the c:\mbuilder\user\models prompt.
  4. Type mb to restart Model Builder.
Additional Information: For technical information on the RIU and its operation refer to the RIU manual.

Testing the Waveform Synthesizer (8AFA):

When to do it:
  1. You suspect you have a faulty 8AFA.
  2. You want to check the audio quality present at the speakers or in the headset.
What it checks:
  1. Audio from the DACS to the headset or speaker by sending a unique tone/signal from each 8AFA channel.
  2. Headset (if used) audio by looping back audio inputs to the corresponding audio outputs.
How to launch it:
  1. From the Model Builder main menu select "Quit".
  2. Type dred_loc at the DOS prompt and press ENTER.

NOTE: If audio starts blaring from your headset or speakers press the F3 key to "freeze" the DACS. Turn down the volume of those devices and then press F3 again to "unfreeze" the DACS.

Checking the audio outputs:
  1. A unique audio signal is sent to each 8AFA channel
    1. CH 1 = Caution tone
    2. CH 2 = Playback of recorded engine
    3. CH 3 = Sine wave sweep
    4. CH 4 = IFF tone
    5. CH 5 = Jamming effects
    6. CH 6 = Stall warning tone
    7. CH 7 = ATIS message
    8. CH 8 = Missile warning tone
  2. Check that the tones are audible and free from distortion, breakup and noise.
Enabling the audio loopback:
  1. From the main menu select "Models" and choose "Model 1, 2 or 3" depending on which 8AFA you wish to check.
  2. Press F2 and choose "Controls".
  3. Use the arrow keys to highlight the "Output_Control" object.
  4. Press ENTER to access this object.
  5. Use the arrow keys to move to the "Local X" field.
  6. Use the +/- keys to toggle this field from OFF to ON.
    1. The automatic tones will cease.
  7. Speak into the microphone and listen for the audio to be looped back to the headset or speaker.
    1. CH 1 input is looped back to CH 1 output and so on for each 8AFA channel.

NOTE: It may be necessary to adjust the 8AFA pre-amp gain to accommodate the microphone you are using. Move to the Waveform DSPs >> Gains page and use the +/- keys to adjust the gain values until the desired signal level is reached.

Restoring the DACS to normal operation:
  1. From the Model Builder main menu select "Quit".
  2. You are now at the c:\mbuilder\user\riutest prompt.
  3. Navigate back to the c:\mbuilder\user\models prompt.
  4. Type mb to restart Model Builder.
Additional Information: For technical information on the 8AFA and its operation refer to the Operation and Maintenance manual.