Considerations for Malicious Call Trace

Last Updated : Nov 12, 2019 |

This section provides information about how the Malicious Call Trace feature functions in certain circumstances. Use this information to ensure that you receive the maximum benefits of Malicious Call Trace under all conditions:

  • If the originator of the call hangs up, the system discontinues the feature. However, if the recipient of the call hangs up, the system does not discontinue Malicious Call Trace.

    Note:

    When the recipient of the call is a DCP or H.323 station, you cannot hang up the call until the MCT Controller deactivates MCT. However, when recipient of the call is a SIP station, you can hang up the call without the MCT Controller deactivating the MCT.

  • Except for Emergency Access to the Attendant, features that usually display information do not display information on the telephone of the Malicious Call Trace controller, when Malicious Call Trace is activated. Except for the display of information, these features function normally until Malicious Call Trace is deactivated.

  • Use an mct-act button rather than the Feature Access Code (FAC) to activate Malicious Call Trace because the FAC requires extra time.

  • Visually Impaired Attendant Service (VIAS) provides spoken display information for Malicious Call Trace activation, but not for Malicious Call Trace control.

  • Malicious Call Trace information on an active malicious call is lost if a server fails while Malicious Call Trace is activated.

  • When you request help from a controller on a server in tandem, the following might occur:

    • The malicious caller might hear a warning tone as a result of the intrusion.

    • You can lose continuity on the trace if the person who activates Malicious Call Trace on the server in tandem is not the Malicious Call Trace controller.

  • If a malicious call comes in on a non-ISDN trunk, the controller must have the telephone number for the connecting server and a cross-reference of system-trunk port numbers. The controller might also need the DS1 channel number.

  • Only H.323, DCP stations, and attendants can be an MCT Contoller. The mct-contr button is not supported on any SIP endpoints.

Differences between Button state and Multiple invocation are as follows:

Button state

Multiple invocation

H.323/DCP phone

The mct-act button lights as soon as you press the button, and it stays lit until an MCT Controller deactivates MCT.

You can press the mct-act button again and invoke MCT a second time, even if your first invocation has not been deactivated.

SIP phone

The mct-act button stays dark when you press the button, and it does not light until an MCT Controller presses the mct-control button.

You cannot press the mct-act button a second time. If you do, you get a denial tone.