TSipClient component with the full source code allows you to create your own SIP softphone, call center application or IVR system.

Make PC to phone or PC to PC calls via VoIP providers
Multi User Conference
Unattended call transfer
Call Redirection
Detect DTMF user input
Record calls and save to .wav files
Play .wav files to the phone line
Play text using Text-To-Speech (TTS) voices
Send DTMF (Inbound, SIP INFO, RFC2833)
Hold calls
Select Audio In/Out Devices
G.711 A-law/Mu-law
GSM.610
Speex
Handle multiple SIP calls at the same time

Home:

http://sipcomponents.com/

Only for V.I.P