If there is a regen (Repeater) on the circuit, the active side will be in the CSR to CO direction. This assumes a T1 NIU that wold be span powered from the same repeater. Of possibly HDSL.
Most tech's change out a component, and when it restores, leave without any further analysis. Unfortunately a good number of Telco tech's do not look at the performance monitoring data that has been collected on both T1 NIU-PM units, or, on HDSL equipment.
At a minimum there are seven days of PM data, plus the current 24 hour period, available to analyze. This would help determine if there were incoming T1 circuit errors based on BPV line (CV-L) or CRC6 path (CV-P) errors.
The key is being able to detect error conditions, especially those that may be transient in nature. The D channe log is helpful from the PBX end, but knowing if there is an inbound trouble helps focus resources. The LEC switch shold havethe capability to monitor the D channel status. Not very fancy, but the camp on monitor available to the %e does help. Now the task si to get the LEC to turn on the D channel monitor at the switch. Or at best, place a protoco analyzer at the CO switch DSX-1 and monitor/trap D channel messages.
If you can get them, LEC, to recognize that a trouble exists on their side ofthe NI, the circuits may get fixed.
Good luck.
Field OPS
Good luck.
