HDSL4 for General Distribution Installation and Maintenance Practice HDSL NEW ENHANCED FEATURE OVERVIEW61223HDSL4L2-5C B-5Splice Detection ScreensChronic Circuit ProblemsThe Chronic Circuit Problems screen (Figure B-2) displays general information about circuitswith bad splices.Figure B-2. Chronic Circuit ScreenNOTESince this detector employs a very sensitive measurement, it isimperative that all obvious troubles be cleared prior to relying onthe splice detection information for troubleshooting the circuit.This is reflected by the following screen statement: “Wire pairs passall electrical tests and meet deployment guidelines.”Splices that are varying in impedance will cause the HDSL data pump to see a reduced and/orfluctuating signal quality (margin). The HDSL data pump will attempt to track these changes,but when the changes become too severe, errors or loss of synchronization result. This isreflected by the symptoms described on this screen. If a circuit meets these criteria, the possi-bility of an impedance-varying splice should be considered.To access a particular menu item, press the number associated with that item, and pressE NTER. The menu options are as follows:• “View Splice Results Screen” on page B-6• “Reset Splice Detector” on page B-6• “View Splice Histogram” on page B-7Press ESC to return to previous menuChronic Circuit ProblemsField experience has shown that many chronic circuit failures are due tobad splices. These type circuits generally have the following symptoms:- Wire pairs pass all electrical tests and meet deployment guidelines.- Large margin fluctuations will occur on the suspect pair. This can be seenon the Detailed Status Screen. (Min & Max margins differ by > 6 dB)- Pairs experience errored seconds (ES,SES,UAS) and/or loss of sync (LOS).- The bad splice will most severely impair the unit closest to the splice.This HDSL unit has the ability to test for bad splices. This detectionshould be used as a last resort after all other loop testing has beendone. The detection is an approximation which can point the technicianto the general area of the suspect splice.(+/- 275 ft). For bestresults, re-splice all splices close to the indicated trouble.1. View Splice Results2. View Histogram Screen3. Reset Splice Detector
