Hello sir, There is an echo problem in sip voip call. I think it is because of delay in audio. Let me try to explain you my system setup. I have test asterisk on two different system. System : 1> OS : Ubuntu(10.04)Lucid System Type : x64-based pc Processor : Intel(R) Core i5 CPU M520 @ 2.40GHz RAM : 4.00 GB System : 2> OS : CentOS (5.7) System Type : x86-based pc Processor : Intel(R) Pentium D CPU 3.00GHz RAM : 1.00 GB I use beetel magiq android tablet as video sip dialer.( http://beetel.quasar.in/magiqII ), which is rebranded version of huawei ideos S7 tablet (http://www.huaweidevice.com/resource/mini/201008174756/ideos/products_s7.ht ml) I use D-link DIR-615 WIRELESS N 300 ROUTER (http://www.dlink.co.in/products/?pid=349) as wireless access point. I have try two android video softphone on my tablet. 1> Voipswitch : http://voipswitch.com/en/products/softphones/mobile-softphones/softphone-for -android/ 2> Linphone (1.2.2) : http://www.linphone.org/eng/download/packages/android.html * i also try both codec( G729 , G711) * android tablets and asterisk server are connected in Local Area Network(LAN). -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.digium.com/pipermail/asterisk-users/attachments/20120116/1ef5a137/attachment.htm>