Echo on Calls

[telcoengineer]

Hey All, 
I have a Mitel5000 with version 6.2.5.82, Digital 8528 phones and AT&T POTS Lines. Users complain of echo (they can hear their own voices in the ear piece) on outside calls. We have ran the Hybrid balance test as well as Loop Loss, I cannot seem to figure out the issue, we have had the issue with IP phones/POTS but never digital phones/POTS.
We have had the issue with others system but once we moved to Comcast POTS lines the problem seems to go away.

Have any others had the same problem?

[Tech Electronics]

telcoengineer,

Have you tried lowering the volume on the handset to see if the problem subsides? If that seems to work then just set the Echo Profile for that phone to be more aggressive. You could also pad the volume on the trunks as well, but I would make that a last resort if it were me.

**** UPDATE ****

I just thought of something else. Do your loop start trunks have the Connected to CO box checked? Also what is the Echo Profile on your Trunks maybe it is causing your problem. Also, make sure that the line specifications [voltage, current, etc..] are within Mitel tolerances for Loop Start Trunks.

Also, they need to realize that it will never just go away as that is a feature called side-tone.

Thanks,

TE

[telcoengineer]

Yes, I should have mentioned that it does the same thing regardless or volume.
 We had a previous system with the same issue and Mitel Support suggested going into OLM and tweak transmit and receive Gain to mask or eliminate the issue. We have tried this as well.
Also we moved phones to another echo profile.

[Tech Electronics]

telcoengineer,

If padding the volume on the trunks didn't do it then it is most likely an issue with the phones not the trunks. Or the customer came from IP Phones and they are not used to hearing side-tone on their phones; not likely.

Thanks,

TE

[Tech Electronics]

telcoengineer,

Try swapping out the phone with a different model and see if maybe it is a firmware issue. I seem to remember that being an issue on a model  of phone a few years back and we had to manually upgrade the firmware on them.

Thanks,

TE

[telcoengineer]

OK,  I think I still have some 8520's or 4400's around.  This is a new system in the beginning of October. When we plugged them in they went through the process of upgrading firmware, I remember that same issue but did not see any errors this time around. . I will try it though.

Admin/Diag shows Version 18.00F7.2E.04  Not sure if thats current.

[acejavelin]

Did you run the Line Quality and Hybrid Balance Tests on the analog lines?

[telcoengineer]

TE

Yes we did run the Hybrid Balance and Loop Loss tests.

[telcoengineer]

TE

In response to your question about the flag for "Connected to CO.  The answer is no.

[acejavelin]

TE

Yes we did run the Hybrid Balance and Loop Loss tests.

Probably a stupid question, but after you switched trunks did you re-run the tests and then manually change the settings to the recommended ones in the Message Print? I believe after the initial test, you have to change them manually, they only auto set the first time. 

[telcoengineer]

TE

I did go through each and verified the settings. Obviously I am not able to change the ERL, but did make sure that the Hybrid Balance was set and if not made changes accordingly.
What I do not understand is the Transmit and Gain, Trunk 94005 dB levels were set to zero before the test, the test results show 3 and 3  I changed the values to 3 and 3 and run the test again and they show 6 and 6.  Is this normal?

-01:207- > -01:195- 14:40 11-09 *** Trunk: ID(1:'94005') Starting Automated Hybrid Balance Test.
-01:207- > -01:196- 14:40 11-09 *** Trunk: ID(1:'94005') Hybrid Balance Setting: 0  Raw Echo Value: 1091  Effective ERL: 4.35 dB, Line ERL: 10.35 dB
-01:207- > -01:197- 14:40 11-09 *** Trunk: ID(1:'94005') Hybrid Balance Setting: 1  Raw Echo Value: 870  Effective ERL: 6.32 dB, Line ERL: 12.32 dB
-01:207- > -01:198- 14:40 11-09 *** Trunk: ID(1:'94005') Hybrid Balance Setting: 2  Raw Echo Value: 461  Effective ERL: 11.83 dB, Line ERL: 17.83 dB
-01:207- > -01:199- 14:40 11-09 *** Trunk: ID(1:'94005') Hybrid Balance Setting: 3  Raw Echo Value: 320  Effective ERL: 15.00 dB, Line ERL: 21.00 dB
-01:207- > -01:200- 14:40 11-09 *** Trunk: ID(1:'94005') Hybrid Balance Setting: 4  Raw Echo Value: 396  Effective ERL: 13.15 dB, Line ERL: 19.15 dB
-01:207- > -01:201- 14:40 11-09 *** Trunk: ID(1:'94005') Hybrid Balance Setting: 5  Raw Echo Value: 396  Effective ERL: 13.15 dB, Line ERL: 19.15 dB
-01:207- > -01:202- 14:40 11-09 *** Trunk: ID(1:'94005') Hybrid Balance Setting: 6  Raw Echo Value: 316  Effective ERL: 15.11 dB, Line ERL: 21.11 dB
-01:207- > -01:203- 14:40 11-09 *** Trunk: ID(1:'94005') Hybrid Balance Setting: 7  Raw Echo Value: 1410  Effective ERL: 2.12 dB, Line ERL: 8.12 dB
-01:207- > -01:204- 14:40 11-09 *** Trunk: ID(1:'94005') Finalized Hybrid Balance Test - Best Effective ERL: 15.11 dB  Optimal Hybrid Balance Setting: 6
-01:207- > -01:205- 14:40 11-09 ***        Transmit Gain: 3 dB  Receive Gain: 3 dB

[acejavelin]

Did you change the values to 3 or -3?  I don't mess with this too much, but I think it is saying the gain is 3db, so you need to pad it down (-3db). Been a while and our test system doesn't have analog trunks, just SIP and PRI.

I guess I generally don't mess with the gains unless it is more than 6db off.

Also, remember that after you run the test, you have to close and reopen DB Programming for the values to be updated.

[telcoengineer]

I changed the values of transmit and receive to 3dB as that what it said. I immediately ran the test again and the output showed 6dB for both transmit and receive.

[acejavelin]

I changed the values of transmit and receive to 3dB as that what it said. I immediately ran the test again and the output showed 6dB for both transmit and receive.

I would set them to -3db or even -6db... you want your analog trunks to be somewhere between 0db to -6db

[telcoengineer]

When we first started this battle we changed the receive gain on the loop start trunks to -3db as mitel had suggested. still the same results.

Ive went through and changed all the trunks to -3 on receive and 0 for transmit.

I contacted AT&T before and requested info on the dB levels of their trunks but was never able to get anywhere. These appear to be traditional POTS lines and not analog from U-Verse.