Trace Call: Identifying Anonymous Callers (Not for U.S.)

You can have the carrier identify malicious external callers. You can save the caller's station number during the call or for 30 seconds after the call ends. However, it is essential that you do not replace your handset during this time. 

Step by Step
	You are engaged in an external call.
	Press the key. LED flashes. Enter the code.     After you have finished tracing the call, the data is stored on the carrier's system. Now contact System Support.