3CX includes a TAPI driver that will allow Microsoft Outlook 2007 to dial phone numbers directly from inside Outlook. The TAPI driver is installed when we install the 3CX Call Assistant software. After you have installed and configured the 3CX Call Assistant, launch Outlook. Open a Contact as shown in the following screenshot, make sure there is a valid phone number entered and click on the Call button:

You will be presented with the New Call window. Here we will click Dialing Options to change the TAPI driver to the newly installed 3CX TAPI driver:

You will now see the Dialing Options window. Set the Connect using line drop-down to the 3CX Call Assistant option and then click OK:

Outlook is now set up to be able to dial a phone number using 3CX.