[asterisk-users] Echo problem in VoIP-calls

[Gareth Blades]

Routers wont cause echo. In order for them to do so they would have to 
store the outbound voice traffic, delay it and then mix it into the 
inbound voice.

Telephones inherently cause echo. For domestic calls the audio path is 
normally so short that any echo arrives back so quick the human ear does 
not detect it. For international calls the telco uses expensive echo 
cancelation technology.
When you switch to voip you are often suddenly introducing a much larger 
delay so any excho which was present before but not noticed suddenly 
becomes noticable.

You need to analyse the audio path your calls are taking, where the 
delays are being introduced and where echo cancelation is being applied.

You also havent stated which end of the conversation is hearing the echo.

Jonas Kellens wrote:
> Hello,
> 
> I also thought about echo because the Zoiper softphone is used with a 
> headset. But that didn't explain why the echo also appeared on the 
> analogue phone + gateway.
> 
> I have the same Grandstream GXW 4008 gateway with 5 analoge phones 
> attached in another environment and there, there are no echo-problems. 
> Can't say the analogue phones that are being used there are top of the 
> bill, rather cheap stuff actually.
> 
> When calling through the analogue phone line, there is no echo (and it 
> seems therefore that the analogue phones that are being used meet the 
> quality standards).
> 
> The only network-element that is different in the 2 environments is the 
> router...
> 
> 
> 
> Jonas.
> 
> 
> On 06/30/2010 11:06 AM, Gareth Blades wrote:
>> Echo cannot be caused by a router.
>> The zoipher softphone is probably being used with a headset and I 
>> suspect the microphone is picking up the sounds from the earphones 
>> resulting in echo. Try turning down the earphone volume to see if this 
>> helps. If it does invest in some better headphone preferably ones where 
>> the microphone has built in background noise cancelation.
>>
>> For the analogue phone it could be a similar issue. Some phones are 
>> better than others. Cant you use a proper SIP phone? They work so much 
>> better.
>>
>>