From Tino Kasubke Software:
You do not have any PBX and would like to install TAPIMaster nevertheless, however, on a trial basis? No problem. The Demo TAPI-Driver emulates a PBX. Please copy the TMDEMO.TSP file into the SYSTEM 32 directory of the server computer. Open the Phone and Modem Options control panel, page Advanced. Add the TAPIMaster Demo Telephony Service Provider. Now you can use the virtual PBX. This PBX supports various features for internal calls.