Friends I want to use A20 for our IP calling project which include Linphone. I confirmed from IGOR that there is no sound issues regarding audio driver while capturing voice from microphone or getting audio  from headphone jack with his debian images. I only have to confirm that did anybody use LINPHONE on A20 debian or trusty system.

Here is a thread regarding VoIP clients on Banana Pi and this is the output of "apt-cache show linphone-nogtk" running Armbian Wheezy:

Package: linphone-nogtk
Source: linphone
Version: 3.5.2-10
Installed-Size: 125
Maintainer: Debian VoIP Team <pkg-voip-maintainers@lists.alioth.debian.org>
Architecture: armhf
Depends: libc6 (>= 2.13-28), liblinphone4 (>= 3.5.2), libmediastreamer1 (>= 3.5.2), libncurses5 (>= 5.5-5~), libortp8 (>= 3.5.2), libosip2-7, libreadline6 (>= 6.0), libspeex1 (>= 1.2~beta3-1), libtinfo5, libx11-6, linphone-common (= 3.5.2-10), host
Description-en: SIP softphone - console-only client
 Linphone is an audio and video internet phone using the SIP protocol. It
 has a GTK+ and console interface, includes a large variety of audio and video
 codecs, and provides IM features.
 .
 This package contains the console version of linphone, which saves space as
 it doesn't link to the gtk libraries. It does however still link to libx11
 for video support.
 .
 Console Tools:
 .
  . linphonec is a command line interface that can use readline on Linux to
  get completion, history, such as bash.
  . linphonecsh is another command line tool to remotely control a linphonec
  daemon. Unlike linphonec, linphonecsh immediately exits once the command is
  executed.
Homepage: http://www.linphone.org/
Description-md5: ea9dc85daac50c5af653e397210d4f6b
Tag: uitoolkit::ncurses
Section: sound
Priority: optional
Filename: pool/main/l/linphone/linphone-nogtk_3.5.2-10_armhf.deb
Size: 50982
MD5sum: 968a6c149225e059c406aa0dd82f8beb
SHA1: 86e3fa464b6e820b877f996789a6e5c755b72d9c
SHA256: 44ee11f2fb6a3ced5d8cb103a1da05575e9a1b5228107efc5efbbdb518e4e938