D105 Auto-Test

AUTO TEST is a one button test sequentially performing all test features of the D105. Once a fault is identified testing stops, and the lower left side provides a conclusion to why the test failed. If no fault is found after all tests have been performed the indicated result is "PASS".

The following list of tests are performed:

  • Basic DC tests looks for battery, shorts, grounds, opens, and unbalanced Tip Ring
  • Load Coil Test counts coils (Pass condition requires no loads present)
  • Noise Metallic and Longitudinal
  • Impedance Balance test
  • Auto-TDR based on DC capacitance length
  • Leakage


The screen to the left indicates the D105 found a Tip to Ring Short. Once the short has been cleared F3 will restart the test from the beginning.


An "OPEN" condition signifies a local connection is missing. Wire lengths in excess of 50 feet will display footage readings.

A ground error is an indication the user forgot to attach the ground cord to the cable sheath, or the sheath is open close to the test set.

Although at first glance it would seem like an open tip, that condition would not increase the ring length beyond that of the Tip to Ring. It is more likely to be an un-balanced condition due to partial bridge tap removal.

Once defined the TDR can be used to locate the fault.

Leakage test is the final test in the Auto-Test sequence.


If the cable design criteria meets or exceeds the bandwidth requirement, this pair should be able to support the DSL service.