Siptapi

Note: Support for SIPTAPI is provided through IPCOM.at. It's possible that the program may not work properly on current operating systems.

Extract the file and open the 'Release' folder, where you'll find two folders: '32bit' and '64bit'. Choose the folder that matches your operating system (tip: you can find this by right-clicking on 'My Computer' and then properties. Here you'll see '32-bit operating system' or '64-bit operating system'.
Copy the 'siptapi.tsp' file from the corresponding folder to C:\windows\system32 (Note: you must have administrator permissions on the computer to do this).

Select 'Phone and Modem Options'.
Click on the "Advanced" tab
Click on "Add"
In the list of available drivers, choose 'SIPTapi <version number>' and then click 'Add'.
SIPTapi service provider now appears in the list of providers. Click on "SIPTapi service provider <version number>" and then press 'Configure'.

Note: A different screen may appear first asking for your area code among other things. Fill this in as completely as possible and press 'ok'

SIP Domain: sipproxy.voipgrid.nl
SIP Outbound Proxy: sipproxy.voipgrid.nl
Leave the checkboxes for Reverse mode and Auto answer unchecked
User: Enter the account ID of your VoIP account here.
Password: Enter the password that belongs to your VoIP account here.
Authentication-user: Leave this empty.
User's extension: The internal phone number of the relevant device (for example 201)
After setting this up, a restart of your computer is necessary to use Siptapi.

With Siptapi, it is now possible to call contacts directly from applications like Outlook.
To do this, go to a contact and right-click on the phone number. Choose "call contact" and press "start call".
Then your own phone will ring, pick up the phone.
The caller will now be called, it takes a few seconds before you hear the phone ringing at the called person's end.
For a detailed manual click here[1]