Echo on External Calls

Discussion in '3CX Phone System - General' started by sbonner, Apr 9, 2013.

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  1. sbonner

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    We are having a problem where a speaker can hear their own echo during a call. The person they are talking to does not hear the echo. Sometimes, it may affect the quality of the voice of the person they called, as well.

    I ran a wireshark and determined that the echo is coming from the PBX side (it doesn't appear in the recording from the phone side). Acccording to the wireshark, the correct G711 codec is being used (I mention this as other threads have suggested the problem is caused by the wrong codecs).

    I have tried to both check and uncheck 'PBX delivers audio' at the affected extension to no avail.
    The VoIP Provider is checked as 'PBX delivers audio'.

    Would anyone have any suggestions on where to look next?
     
  2. leejor

    leejor Well-Known Member

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    I assume that the echo is only on outside calls over the VoIP provider? Is this on all outside calls, or only some? Local or long distance calls?

    What type of sets are you using? All the same type? A mix of sets? Does it happen on all of them?

    Has this been going on for a while or did it just start recently? If recently, have there been any changes done on the local LAN, perhaps about the time the trouble started? Do you have any other outbound trunks to try calls on?

    If a person at a 3CX extension hears echo, it is their own voice, with enough of a delay to be annoying. So, either the voice level is going out at too high of a level, or there is sufficient delay (perhaps more than usual, caused by a delay in the network) and lack of echo suppression at the far end. Tracking it down, unfortunately, can be a bit of a cat and mouse game.
     
  3. sbonner

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    We believed that it was only on inbound calls, but we finally caught an outbound call where the echo also occurs.

    Yes, it happens on external calls going out on the VoIP provider (nexVortex), the vast majority of the time. Occassionally, a call will be clear. Other times, the echo will begin a few seconds into the call. When calling the affected users, I've noticed an audio anomaly on my end at the VERY beginning of some call (the first sound to be heard on the call) that sounds like a shearing robotic crackle. After that, I hear no other problems but the other user still has the echo. (It does not occur all the time, but when it does occur I can almost gaurantee that they've got echo.)

    We are using Grandstream phones (2100's, I believe, or 1450's). The echo occurs on -all- phones and occurs when directly going to an extension or when dialing through a ring group. I did a wireshark and determined that the audio leaving the Grandstream phones was clear; the echo can be heard on the returning audio from the PBX/provider. I am not an expert user of Wireshark, though, so I wasn't able to determine much else other than the fact that there appears to be no errors.

    The network is extremely simple; I'm not sure where the latency would be coming from.
     
  4. leejor

    leejor Well-Known Member

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    If you had a second provider, you'd be able to see if it were only calls through one, or both. Without being able to eliminate/substitute something, I'm not sure where you would go next.

    At this point I could only speculate that it is either your internet connection, or your VoIP provider.

    Have you tried enlisting the help of your VoIP provider, they may have some insight?

    Did this just start recently? Is this a new installation? Is your internet connection being used heavily for other data (non-VoIP)?

    If all phones are the same make, you might consider installing the 3CX phone on a laptop and doing some test calls. At least that would eliminate the current sets (firmware/settings) as the issue.
     
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