This is set up within your computer. You can select whichever Voip program to be the default program to run/use when clicking phone numbers within Vincere. 

1.Make sure that you install the default program you want to use. 

2. If you are using windows 10, Just search for  "Default app for" 

3. Once there, scroll down and locate "TEL" 

4. Click on the app on the right side and select your preferred default program.  

In the example below, I have Skype selected but you can also click it to select a different program.    

 Once you've completed this, you can now use your preferred program whenever you click on a phone number within Vincere.