i find the problem,but i don't clear about it.
i see a article named 'Tapi 3.0 Application development using C#.NET By devang_bison' in the http://www.codeproject.com
the link : demo and source
look at this code script:
bcc = ln.CreateCall(textBox1.Text,TapiConstants.LINEADDRESSTYPE_PHONENUMBER | TapiConstants.LINEADDRESSTYPE_IPADDRESS,TapiConstants.TAPIMEDIATYPE_AUDIO);
CreateCall is no problem,but bcc.Connect throw out an expection.I change to
bcc = ln.CreateCall(textBox1.Text,TapiConstants.LINEADDRESSTYPE_PHONENUMBER ,TapiConstants.TAPIMEDIATYPE_AUDIO);
the program can run.I think it's maybe the computer not support the TapiConstants .In my opinion,it's best to use one TapiConstants.
Latestly,I study how to play the music to the recieve when using the computer telephone.I hope get help,thanks!