TAPI Integration - Microsoft Outlook Click-to-call

What is TAPI and how do I configure it?

The SIP TAPI is a TAPI driver, which enables SIP click2dial functionality from TAPI applications (like MS Outlook, Phoner ...). The correct term for this application is: A service provider for the MS telephony API.

How does it work? - The SIP TAPI sends an INVITE request to your own SIP phone. When you pick up the phone and the call between the SIP TAPI and your phone is established, the SIP TAPI sends a REFER request to your phone. This REFER request contains the originally called phone number in the Refer-To: header. Thus, your SIP phone will establish a new call to respective phone number. For a detailed howto please refer to the SIPTAPI-Tutorial.


Download the TAPI here:  [This is 3rd Party Software and used at own risk]

  • Copy the siptapi.tsp file into \windows\system32\
  • Install the TAPI driver via the control panel: Start -> ControlPanel -> PhoneAndModemOptions -> Advanced -> Add -> SIP TAPI Service Provider

Configure via the control panel: Start -> ControlPanel -> PhoneAndModemOptions -> Advanced -> Configure

  • SIP domain: the domain of your SIP URI
  •  - Outbound Proxy: the IP address or domain of the Host
  •  - username: the SIP username from the control panel
  •  - password: the SIP password from the control panel

The SIP TAPI does not support for NAT traversal. Thus, you must register to a SIP proxy which does the NAT traversal, or use a dedicated outbound proxy.
Configure the TAPI:

  • SIP domain: sip.voicehost.co.uk
  •   outbound proxy: sip.voicehost.co.uk
  •   user: seat user-name
  •   password: seat password

You should now be able to dial using the TAPI.

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