The acoustic echo cancellation software uses OpenH323 version 1.13.4 as baseline. If you have installed openh323 in ~/openh323, go to your home directory, open the tar-ball and compile the simph323 with the following commands: cd ~ tar xzf simph323_aec_1.0.tgz cd openh323/samples/simple make opt If you start the program with ./obj_linux_x86_r/simph323 -n -e -l -a you should get SimpleH323 Version 1.13.4 by OpenH323 Project on Unix Linux (2.4.21-99-default-i686) Local username: anblf Silence compression is Disabled Auto answer is 1 FastConnect is Enabled H245Tunnelling is Enabled Jitter buffer: 50-250 ms Sound output device: "/dev/dsp0" Sound input device: "/dev/dsp0" Codecs (in preference order): Table: iLBC-15k2{sw} <1> iLBC-13k3{sw} <2> GSM-06.10{sw} <3> MS-GSM{sw} <4> G.711-uLaw-64k{sw} <5> G.711-ALaw-64k{sw} <6> SpeexNarrow-18.2k{sw} <7> SpeexNarrow-15k{sw} <8> SpeexNarrow-11k{sw} <9> SpeexNarrow-8k{sw} <10> SpeexNarrow-5.95k{sw} <11> LPC-10{sw} <12> UserInput/hookflash <13> UserInput/basicString <14> UserInput/dtmf <15> UserInput/RFC2833 <16> Set: 0: 0: iLBC-15k2{sw} <1> iLBC-13k3{sw} <2> GSM-06.10{sw} <3> MS-GSM{sw} <4> G.711-uLaw-64k{sw} <5> G.711-ALaw-64k{sw} <6> SpeexNarrow-18.2k{sw} <7> SpeexNarrow-15k{sw} <8> SpeexNarrow-11k{sw} <9> SpeexNarrow-8k{sw} <10> SpeexNarrow-5.95k{sw} <11> LPC-10{sw} <12> 1: UserInput/hookflash <13> UserInput/basicString <14> UserInput/dtmf <15> UserInput/RFC2833 <16> Waiting for incoming calls for "anblf" Press X to exit. H323>