1. Download Linphone here and install.
2. After installation, check the corresponding box and click “Use SIP account” button.
3. On the second screen click “I understand”.
4. On the next screen enter the following data:
User name: 111111 (where 111111 is your SIP login from your personal account)
SIP domain: sip.zadarma.com
Enter SIP login password from the personal account
In the Transport field enter UDP.
User name: 1234-100 (where 1234-100 is your PBX extensioin number from personal account)
SIP domain: pbx.zadarma.com
Password: Your PBX extension number password that needs to be generated on "My PBX - Extension numbers" page in your personal account
In the Transport field UDP.
5. Then, in the top right corner click on the login you have just created and change the status to “Available”.
The installation is complete, you can make calls.
6. If everything is set up correctly, you will see a message "Registration is successful"