TAPI - How does it connect?

How does TAPI connect to my telephone line?

Years ago I wrote a visual basic phone dialer which has worked fine for years using Com 3. Historically I have also used software called PhoneTrayFree that provided Caller ID and provided selective call blocking. I would simply, in code, “kill” that process when I ran my dialer and then reinstate when the later closed. With a new USB modem and Windows 10 my dialer will not connect showing another program using the COM port. It is not PhoneTrayFree and I cannot identify, but found a workaround using TAPI in my Visual Basic dialer code - no more Com number.

I am 88, my fundamentals are weak, fear they never will be strong but hopefully can understand how TAPI avoids the COM ports, the old 9 pin serial connections.

Ed
Windows 10, 21H2 Build 19044.1348
Home built two years ago using ASRock H270M Pro4 motherboard and Intel i5 7500 CPU and cannot handle Windows 11

Spunk: Read you but think I will avoid the Tek Tips forum recommended which is designed specifically for IT Professionals. Twenty eight years retired I am strictly a hobbyist now helping other old retired Windows users but still maintaining my old VBA and VB.Net coded personal utilities. I will check out Microsoft's VB forum first trying to learn a bit more about TAPI and then getting into Windows confusing utilities under Device Mgr that make difficult identifying COM port use.

Thanks again - missed how to say "Answered."

Hi,

I know it's old stuff, but this example is for tapi 3.0 and Windows 10 uses tapi 3.1, I believe this snippet could lead you in the right direction.

FreeVBCode code snippet: TAPI (Telephony API) Demo

Thanks Malo K,

Actually I have modified the one dialer utility I wrote years ago which used the Serial Port Control to open a port and then dial. I replaced the Serial Port control with the function tapiRequestMakeCall in the Tapi32.dll. Works great but was interesting in just a bit better understanding of how TAPI connected to whatever USB port (which I suspect) when I see no evidence in Device Mgr. When you used a COM port it could be identified and the process using identified.

But thanks it does give me something more to read and maybe there is some hope for this old man leaning some basics.

Ed