Echo on anlogue trunks

[amilalex]

We have installed 3300 ICP MX controller with 6 analogue trunk lines and an ASU II with a 4+12 combo card with two analogue.

When making an external call from an IP Phone using one specific trunk on the controller and one on the ASU, there is echo for about 10 seconds. After this time period, it stops. The telecom lines are fine when checked with direct analogue phone connection. We have tested default configuration...

We have tested the analog trunks. We did LMS and set up the PBX according to its results, but still have echo on those two trunks. All the other trunks are working fine. Have a ticket open with Tech support but they have not been able to assist as of yet.

Have any ideas?

 

[nytalkin]

in ESM go to trunk descriptor for co trunks modify the transmission parameters and test until you get acceptable results. suggest probably selecting "short"

NO GOOD DEED GOES UNPUNISHED!

 

[IrwinMFletcher]

Can you clarify your configuration? You have an MX with 6 trunks programmed (LS I assume), which you have connected to an ASU II with one card. Four of the trunks are connected to the trunks circuits, the other two are connected to analogue ports?

If you call out the trunks connected to the LS ports, things are fine, but not when you call out the ports connected to the ONS ports, correct?

 

[slapin]

I had similar issues with lines from old CO. Try to play with answer supervision parameters.

 

[amilalex]

Irwin in total I have 8 LS trunks, 6 on the AMB of the MX controller and 2 on the ASU 4+12 combo card. 6 of them work fine i.e 5 on the AMB and one on the combo card. The other 2 have echo for the first few seconds (6-8 secs) of the call then it normalizes. I have tried moving them to the two spare positons on the combo card but with the same results. When the trunks are diconnected from the system and I use my test set there is no echo. All the LS trunks use the same circuit descriptor and class of service. I have also tried the answer supervision parameters but no luck yet.

 

[IrwinMFletcher]

Ah, the AMB part was what I was missing.

The important thing to remember is that not all trunks are created equal. What were the results of running the Line Measurement Tool? It sounds like you'll need a new CirDesc for the 2 other trunks, set to a different impedence. Post your LMT results if you have them.

 

[slapin]

As IrwinMFletcher mentioned not all trunks will come from the same board in the CO and have the same path. Call your carrier and ask for test numbers. Run LMT on each trunk separately. You may need to setup tone detection plan as well.