3300 Delayed audio / Echo on Analog Trunks

[kwbMitel]

3300 Rel 9.0 UR1
CX Controller using AMB (Also a MX-200 Controller)
Trunks set for DTS (no ARS)
Sets all 5330's
Also tested via DISA to remove sets from equation.

I very rarely work with analog trunks and have come across the following.

If the analog cct descriptor has "Audio inhibit before answer supervision" enabled (default setting), outbound calls will have delayed audio where the caller can hear the call being answered but cannot respond for about 5 to 10 seconds.

If the the option above is disabled, the caller can be heard but the system has echo (or excessive sidetone)for roughly the same timeframe and then the call becomes clear.

I can live with this, and so can my customer but it seems odd that I have to choose between 2 annoying faults.

Has anyone run into this, found a solution, or felt the need to commiserate?

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Occam's Razor - All things being equal, the simplest solution is the right one.

 

[IrwinMFletcher]

The Answer Supervision option waits for signalling from the CO before it connects the outgoing leg of the call, I would guess then that your CO doesn't provide this, timers kick in and it ends up connecting the call anyway (or the CO waits a long time before providing it). So check with the CO to see if they provide it.

Independent of that, you need to run the LMT if you haven't already. Trunk lines need to be matched to the far end impedance. The reason you don't get echo in the first scenario is simply because the system hasn't connected the portion of the leg that would present it to you yet, but it's still there in the first scenario. It's just not being sent to your phone so you can hear it.

If you've run the LMT and still have problems, then there are other things to try, but that's the first step. Let us know.

 

[kwbMitel]

Regarding LMT, I enabled the option below in the Analog Trunk Assignment. I turned the off/on after connecting the trunks.

Auto Select
Select Yes if you want the system to automatically apply the recommended Impedance and Length settings from Line Measure Tool tests to LS trunks. Select No if you prefer to manually configure the settings in this form.

Note that when you

-change this option from No to Yes, the system automatically runs a Line Quality Measure test on the LS trunk. The system applies the recommended settings to the LS trunks.

-change this option from Yes to No, the system automatically runs a Line Quality Measure test on the LS trunk using the current settings that are entered in the Balance Network Setting field and Trunk Category field, and updates the trunk with these settings.


Regarding the CO and answer supervision. Extemely unlikely this would get anywhere. Not worth the bother.

The comment regarding the echo rings true. Hard to hear yourself echo when nothing is being sent.

Thanks for the insights.



*******************************************************
Occam's Razor - All things being equal, the simplest solution is the right one.

 

[IrwinMFletcher]

What were the results of the LMT? Red, Yellow, Green? What was the ERL?

 

[kwbMitel]

The Help files said that the LMT is run automatically and the settings applied. I did not observe any results.

*******************************************************
Occam's Razor - All things being equal, the simplest solution is the right one.

 

[IrwinMFletcher]

You have to first configure your system to run the tests (either provide the CO milliwatt number or run it in loopback mode). Then run the tests through ESM (Maint/Diag-> Line Quality Measurement).

It's only 'automatic' after you've first configured your system.

Check out the help "Measuring LS Trunk Line Settings", run the tests and post the results if you still have problems.

 

[slapin]

I found that Changing Answer supervision settings may help. Use fake Answer supervision and Answer supervision expected options. Or some other combinations of Supervision signals processing. This echo caused by DSP processing progress tones and being connected for this period of time to the voice channel.IMHO. I have it once in a while with old CO.