Well it's either the equipment on either end or the circuit itself. Have you stress tested the T-1? Sometimes the circuit will go out and not reset by itself.
How is the circuit configured ? (AMI, B8ZS etc.). Test the hell out of the circuit, loop up the far end and then run the tests - All 1s, then All 0s (if it's B8ZS) then 3-24, then QRS.
If that passes, have the LEC go Head-to-Head with you (tester to tester, no equipment at each end. Prove the circuit and then work on the equipment.
Sam
