* 
or later**.**
If you rotate the dial to SETUP and select Twisted Pair - Test Limit – Application you will find an entry called "DTX PL Self Test".
To run this test, you must have the optional DSP-PLCAL Calibration Artifact. Remove the Personality Modules from the end of the Permanent Link Test Leads and connect them to the DSP-PLCAL Calibration Artifact as shown below:-
Now run the test. This is a very strict / tight test. Expect small margins. We have set the limit deliberately tight. There is no such thing as a Good Pass. It either Passes or Fails. If it should fail by more than 0.5 dB, you should recalibrate the Permanent Link Adapters.
Example Test Result:
In this example, we see that the Return Loss margin was only 0.3 dB. This is normal. Again, we are using very tight limits here.