Microsoft Office Communications Server 2007 VoIP Test Set enables you to simulate a SIP endpoint to test connectivity.
Emulation options include the following:
Client emulation - To emulate a Microsoft Office Communicator client, you specify a SIP-enabled user account to register with Office Communications Server. This can be useful for troubleshooting problems with incoming or outgoing Enterprise Voice calls.
Server emulation - You can use VoIP Test Set to emulate a Mediation Server or a gateway. To emulate a server, you specify the IP address, port number, and other settings of the server to be emulated. This can be useful for emulating components during the setup of the Office Communications Server 2007 infrastructure to verify the functionality of components that have already been deployed.
Download here..Voip Test Tool