Blink is a free SIP softphone client for linux. Note that Blink does not have a traditional dial-pad. The developers decided that it's not necessary as you can enter numbers directly via keyboard or call existing contacts.

It's not available in the debian default repository but from a third party.
Create a new apt sources file for blink:

sudo vi /etc/apt/sources.list.d/blink.list

and add the following repositories:

deb    http://ag-projects.com/debian stable main 
deb-src http://ag-projects.com/debian stable main

Add the gpg key for the repository:

wget http://download.ag-projects.com/agp-debian-gpg.key 
sudo apt-key add agp-debian-gpg.key

For Blink 2.0.0 on Linux Mint or Debian Jessie, packages from the unstable branch are required. Those packages have been ported back to Jessie and are available in the jessie-backports repository. Add this repository to your apt sources file (/etc/apt/sources.list or /etc/apt/sources.list.d/official-package-repositories.list)

deb ftp://debian.serverspace.co.uk/debian/ jessie-backports main contrib non-free

then do an

sudo apt-get update

Linux Mint does not include multimedia codecs any longer. This includes ffmpeg libraries and several others required for Blink's video functionality. Even though this is not essentially required for the phone part, the sipsimple package cannot be installed without them.

Copies of the dependencies are stored on the amati file server in /software/it/linux/blink and consist of the following libraries:

libavcodec-ffmpeg56_7%3a2.8.6-1~bpo8+1_amd64.deb
libavformat-ffmpeg56_7%3a2.8.6-1~bpo8+1_amd64.deb
libavutil-ffmpeg54_7%3a2.8.6-1~bpo8+1_amd64.deb
libsnappy1_1.1.2-3_amd64.deb
libsoxr0_0.1.1-1_amd64.deb
libssh-gcrypt-4_0.6.3-4+deb8u2_amd64.deb
libswresample-ffmpeg1_7%3a2.8.6-1~bpo8+1_amd64.deb
libswscale-ffmpeg3_7%3a2.8.6-1~bpo8+1_amd64.deb
libx265-59_1.7-4~bpo8+1_amd64.deb

Copy these into /tmp on the target system, then install all of them using

sudo dpkg -i /tmp/lib*

Now, you can install blink with all dependencies in descending order:

sudo apt-get install python-application -t jessie-backports
sudo apt-get install python-otr -t jessie-backports
sudo apt-get install python-sipsimple -t jessie-backports
sudo apt-get install sipclients -t jessie-backports
sudo apt-get install blink -t jessie-backports

Finally, the default ring-tone of Blink is a high-pitched noise which is more annoying rather than a good ring-tone. Any wav file can be used as ring tone, but the ring tone of Bria is copied it as ''ring.wav' in the software/it/linux folder on the Amati network drive.

Download ring.wav and save it on your system. Then rename the original Blink ring-tone and then copy the Bria ring-tone instead:

sudo mv /usr/share/blink/sounds/inbound_ringtone.wav /usr/share/blink/sounds/inbound_ringtone.wav.orig
sudo cp ring.wav /usr/share/blink/sounds/inbound_ringtone.wav

Now start Blink from the menu, configure desired SIP accounts, set the input/output/alert devices, add contacts and you're ready to go.

Default Preferences:

Settings:
Setup existing SIP account. 
  User: 11xx@amati.hosted.surevoip.co.uk and respective SIP password

Blink -> Preferences:

Accounts: 
Set Display Name
Media: opus/G722, PCMU/PCMA, set Send inband DTMF, opportunistic encryption
Server: UDP
Network: don't use ICE, MSRP Transport: TLS
Adv: 600,600,600,+,None

Audio: enable echo cancellation, sample rate 32000

Adv: Enable UDP, TCP, TLS tranport with Auto port
RTP ports 500 starting at 50000

Disable bonjour account by unticking the 'use account' option.

Delete all contacts by right-clicking the entries and selecting delete.

Use the [+] sign in the lower left corner to add new contacts as necessary.

Testing of Audio configuration and network settings can be done using the
  SureVoIP echo test number *9196

sudo apt-get install darcs
mkdir blink-source
cd blink-source
darcs get http://devel.ag-projects.com/repositories/blink-qt
  (incremental changes to repository: darcs pull -a)
cd blink-qt
sudo apt-get install cython
sudo apt-get install python-dev
sudo apt-get install libvncserver-dev libgnutls28-dev libjpeg-dev zlib1g-dev

sudo apt-get install python-pyqt5 python-pyqt5.qtwebkit python-pyqt5.qtsvg

#cheating:
vi blink/contacts.py
  search for schedule and remove the ,schedule=true from the network-io
vi blink/screensharing/vncclient.py
  remove the import RDBClient, RFBClientError

sudo python setup.py install


do not use: sudo apt-get install cmake (wrong version)

making cmake 3.4 (required for libvnc)
wget http://www.cmake.org/files/v3.4/cmake-3.4.1.tar.gz
tar -xvzf cmake-3.4.1.tar.gz
cd cmake-3.4.1/
./configure
make 
sudo make install 
sudo update-alternatives --install /usr/bin/cmake cmake /usr/local/bin/cmake 1 --force 

sudo apt-get install libpng12.0

sudo apt-get install libsdl1.2-dev
sudo apt-get install libssl-dev libssl1.0.0
sudo apt-get install libgcrypt11-dev

cd ..
mkdir libvnc
cd libvnc
wget https://github.com/LibVNC/libvncserver/archive/master.zip
unzip master.zip
cd libvncserver-master/
mkdir build
cd build
#sudo cmake ..
sudo cmake .. -DWITH_SYSTEMD:BOOL=OFF
sudo cmake --build .