NEC UNIVERGE UM8000 User Manual page 321

Phantom Calls
A phantom call occurs when a phone rings, the phone is answered, but there is no caller on the line. Phantom calls from
the messaging system might be caused when:
• a caller using the messaging system dials an extension, then hangs up before the transfer is completed.
• a subscriber checking messages initiates a return call, then hangs up before the call completed.
• the system attempts to lamp a subscriber's message waiting indicator with an incorrect code.
During call transfers, the messaging system relies on the phone system or the central office to provide an immediate
disconnect. Sometimes the pause between the moment the caller hangs up and when the phone system signals the
disconnect is long enough for one or more ring cycles.
In certain circumstances, such as when the caller or subscriber is connected to the system from an analog extension or
an analog trunk, the phone system does not provide a disconnect signal.
Confirm that the correct phone system is selected on the
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