|Open FTS Threshold and Distance Measurement|
Occasionally one or more pins of a Front Tap Shoe will not seat properly when attached to a Cross-Box or Frame. This results in poor conductivity and inaccurate distance measurements on spare pairs. This is indicated in the DaVaR Test result column of the DaVaR Test Engine by OPEN FTS or NDT. The following describes different conditions that can cause this result.
If the Ring-Tip capacitive distance measurement is less than the Open FTS Threshold, the Test Engine will mark the pair as OPEN FTS.
Starting with software build version v22.214.171.124, the value may be found on the Capacitance tab of the Profile Editor as shown in Figure 1. The default value is 10ft but may vary by customer in future versions. Obs.: The user must use the administrative password in the Configuration program to modify this value.
Prior to v126.96.36.199 the value was stored in the Windows System Registry and was not easily modified. The default value for version prior to v188.8.131.52 was 50ft. To modify this value please call technical support.
95% Unbalanced Pair
If a pair is greater than 95% unbalanced then it will be marked as OPEN FTS.
In some situations the Ring-Tip distance measurement is greater than the Open FTS Threshold but either the Ring-Ground or Tip-Ground legs measure zero or a some other very short distance. This typically leads to a pair that is greater than 95% unbalanced. If you find a pair that has a Ring-Tip distance greater than the and is marked OPEN FTS, please check the unbalanced percentage before proceeding. The unbalanced percentage value may be found in the Zoom View of the Test Engine or the Test Result Details tab of the DaVaR Editor.
NDT and Working Pairs
Occasionally, there will be an open FTS pin on the Tip-Ground (or low voltage) side of a working pair that will cause an NDT result. To diagnose this problem, examine the detailed voltage values in the Test Engine Zoom View or Editor Test Result Details screen. Typically, in this situation the Ring-Ground and Tip-Ground DC voltages will show normal POTS voltage levels but the Ring-Tip voltage will be at or near zero VDC.