Help needed on Java Telephony............!!!!!!!!!!!!!!!!!!

Hi!
I am quite new to Java Telephony. I have downloaded the JTAPI1.2 documentation and class files from the sun site. I want to make an outgoing call from my PC and have wrote a program for doing so. But when I run this program I am getting the following exception :

javax.telephony.JtapiPeerUnavailableException: JtapiPeer: DefaultJtapiPeer could not be instantiated.

Can anybody please help me regarding what other software and hardware implementations do I need to test this program successfully. I am using the following lines of code to get the DefaultJtapiPeer :

Provider myprovider = null;
try
{
JtapiPeer peer = JtapiPeerFactory.getJtapiPeer(null);
myprovider = peer.getProvider(null);
}catch(Exception excp)
{
System.out.println("Can't get Provider : "+excp.toString());
System.exit(0);
}

Thanks in advance. Take Care.
Ankur.....