[asterisk-users] High delay from Asterisk as PSTN simulator

Kevin P. Fleming kpfleming at digium.com
Wed Sep 14 10:31:26 CDT 2011


On 09/14/2011 10:14 AM, Eric Wieling wrote:
> If I read Kevin's post correctly, his statement applies to ALL echo cancellers, not just software EC.

That's correct; regardless of whether the EC runs on a DSP or on the 
host CPU (or is a device in the path of an T1/E1 circuit), if it can 
only handle a 16ms window for echo cancellation, then having a 
packetized 'hop' in the audio path is likely to make it unable to do its 
job at all.

Echo cancellers used on networks where packetized audio is transported 
through at least one hop need to be configured for (at least) 64ms 
windows, if not 128ms.

-- 
Kevin P. Fleming
Digium, Inc. | Director of Software Technologies
Jabber: kfleming at digium.com | SIP: kpfleming at digium.com | Skype: kpfleming
445 Jan Davis Drive NW - Huntsville, AL 35806 - USA
Check us out at www.digium.com & www.asterisk.org



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