atcomsystems.ca/forum Forums Wiring - Telecom Carriers - Trunks & Services T1's, CSU's and DSU's HDSL H4 Problem

Found this forum searching for an answer to my H4 hdsl issue.
This circuit is taking 1 ES every minute. Pairs meter clean, no BT, loads, or other cable faults. At the doubler tried new card & slot & it still fails. Tried all the spares in the same 100 pair group & same thing. Fail. Tried changing to regular adtran & pair gain & it still takes the incremental ES.
Went to the main splice before the doubler & same issue.
Don't know what to do now. It's been 3 days & no solution. Something seems to be interfering with the 100 pair group, but what? I did try to test 2 other pairs in a different 100 pair group & it did pass the powerlid, but I can't use them since they don't go to my terminal & also they are reserved for a service order.

Since all the pairs seem to be affected have you checked the bonding and grounding of the cable/count?

Look at the lights on the NIU's at the CO and customer. Are any solid red? Are any green going to yellow? Do the yellow HCRC lights come and go out then come on again? Remember the CO unit and the Remote customer end unit are in constant comunnication with each other. Since you have a doubbler what do those lights look like? Have you looped the doubbler from both the customer end and CO end and run your tests?

CO UNIT ------------Dbblr-----------Remote (cus)
L1,L2<=============>L1,L2
L1,L2<===========>L1,L2

Are L1 and L2 lights solid green at the Doubbler?

Lights all green@ repeater, doubler & niu. All have been changed out many times. Seems like there is some sort of interference causing the circuit to fail. There are around 40 other hicaps in the same 100 pair count.

Stop wasting your time changing cards. If the L1 and L2 lights are steady green between the CO unit and the doubbler and the doubbler and the remote unit and the L1 and L2 lights do not flash or go solid red or the HCRC light does not go flashing or steady yellow your trouble is not on the cable. HCRC stands for HDSL Cyclic Redundency Check. It does a calculation on the path between the CO unit and the remote unit through the doubbler over the cable. If it does not get the right answer the HCRC flashes. It will flash as long as the trouble that causes the mis calculation remains. At turn up it will be on for about 30 minutes after you complete all testing then goes out.


Have you looped the doubbler back to the CO unit and ran your tests from the DSX. Have you looped the doubbler from the remote and ran your tests to the demarc?

Where are you seeing the errors -- with a test set in a monitor port at the DSX-1 or NIU, customer equipment or the PMs in the network?

I have not done any testing from the dsx. We can only test from the frames.
errors are seen on pms @ the niu. I have also done a cart test & it fails. When I powerlid from the frames out it fails within 30 seconds when the es pops in.

Are you seeing Errored seconds, Severly errored seconds from the network (DSX) to the CO unit or from the CO unit to the Doubbler or from the doubbler to the Remote card and vice versa. Are they unavailible seconds are there any Unavilble seconds?

What brand card is in the CO the doubbler the remote?