HDSL4 for General Distribution Installation and Maintenance Practice Control Port Operation61223HDSL4L2-5C 47Chronic Circuit GuidanceSelecting the Chronic Circuit Guidance option displays the Chronic Circuit Problems screen(Figure 43). This screen provides general information about circuits with bad splice connec-tions as well as a menu to the Bad Splice Detection feature.Splices that are varying in impedance cause the HDSL transceiver to see a reduced and/orfluctuating signal quality (margin). The HDSL transceiver attempts 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 the criteria listed on the screen then the possibility of an impedance-varyingsplice should be considered.Figure 43. Chronic Circuit Problems ScreenTo access a particular menu item, press the number associated with that item, and pressE NTER. The menu options are as follows:• “View Splice Results” on page 48• “View Histogram Screen” on page 49• “Reset Splice Detector” on page 49Press 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
