atcomsystems.ca/forum Forums Wiring - Telecom Carriers - Trunks & Services T1's, CSU's and DSU's From CCB block RX PAT SYNC, no TX PAT SYNC

Hello, I am a telecom tech working on a trouble Tkt that is causing me to have sleepless nights. Westel T3 shelf is terminated to (2)50 pin 66-blocks RX and TX (via amphenol cable), seperated by bridge clips right side TELCO and left side CUST. Running pattern QRS, All 0's via H2H testing is clean on my RX (any errs sent is rx'd), however, tester at DCS cannot sync with me (massive errs). Pattern Sync only on All Ones. Levels taken at block are -0.3dB and 5.7Vpp.

Tester loops NIU clean running 15 min. No errors. When I loop T-T / R-R on same block, tester test clean through loop. Originally, thought it was my testset, however, I replaced it with another test set and cables and get same results.

Strangest thing however is whenever TELCO gets involved either Vendor meet or via telephone. Problems seems to clear itself up. TELCO access point is closer than mine, however, when they moved to the farthest point, no errors.

In addition, TELCO came out to site and ran clean using my equipment. No settings changed. Again, problem appears to be on TX side, however, proving it to TELCO is another matter. If you have any suggestions on what I might look for I would very much appreciated it.

Thank you!

Moving to T1's, CSU's and DSU's.

-Hal

Have you checked the wiring from the amp connector to the 66 block carefully? I've seen similar kind of troubles occur when you have a tip or ring mixed up with an adjacent pair. Might be kind of hard to verify with that layout, but what you can try to do is change timeslots on the DS3 to send it to a different pair to see if it makes a difference (since you'd be on a different pair on the block as well, unless they happen to be consistently wrong).

I remember experiencing a very similar trouble on an install awhile back. A tech before me had mounted a bix panel in a telephone room that was crossconnected to a patch panel in another room. Silly me, I followed cabling standards and made a patch cable for where my signal should have been... I was confused at first since the telco test center I was working with could see a hard loop back that I would place on the patch panel just fine but couldn't run to the CSU I had on the other end of it with a straight-through cable connection.

Turned out that my Tx ring was not where it was supposed to be and was one pin over. I guess there was enough signal bleed that people could run to a hard loopback at that point.

Amazing how the simplest of things can cause you the most grief.