This multiline verision of SIPTAPI is essentially an improved version of the original Source-Forge SIPTAPI. It requires REFER support on the SIP side to work properly - but it is stable and tested with various SIP phones (SNOM, Eyebeam, Asterisk) and various TAPI application (Outlook, dialer.exe, phoner). (Currently tested under Windows XP, Windows Server 2003, Windows 7 and Windows 8 (32+64bit)

One major advantage of the multiline version is the use on multiuser-systems (like Citrix installations). The GUI currently supports configuration of 40 lines. Unlimited number of lines are supported if the SIPTAPI configuration is done directly in the Windows Registry, e.g. generate a .reg file and import the settings into the Registry. For each user a dedicated line will be configured - these lines are available globally to all users. Therefore, the user has to choose its respective TAPI line in the TAPI application (e.g. Outlook).

This version also has support for incoming call indication. This means, incoming calls (including caller-ID) will be signaled to the application via the TAPI layer.

Note: SIPTAPI does not allow complete remote control of the SIP phone. Thus, SIPTAPI does not support to answer or redirect/transfer the incoming call. Also, SIPTAPI can not detect if an incoming call was answered or canceled, or the duration of a phone call.

Note: Outlook does not support incoming call indication. Therefore, if you want incoming call indication in Outlook you have to install 3rd party TAPI applications with Outlook support, e.g. http://www.tapicall.com/ or http://www.identafone.com/poppro.html

Further, SIPTAPI is not a media provider and thus it can not handle media at all. You still need a normal SIP phone to answer the call. The incoming call indication is successfully tested with Windows' dialer.exe (XP), Phoner, TAPIMaster Line Watcher and several CRM applications.

The configuration GUI of SIPTAPI is limited to 40 lines because more lines don't properly fit on the screen. But if you configure SIPTAPI directly via the Windows Registry (instructions are provided) there is no limit of concurrent lines (sometimes TAPI applications may become slow if there are too many lines).

For incoming call indication SIPTAPI registers to the SIP server. If the SIP server supports multiple registrations (e.g. Kamailio, FreeSwitch) under the same SIP account then it should work out of the box. If not (e.g. Asterisk), then you need to provision a dedicated SIP account for SIPTAPI and configure the SIP server to ring both extensions on an incoming call.