IP Office Message Waiting Indication
IP Office Message waiting indication (MWI) is a method IP Office uses to set a lamp or other indication on compatible telephones when a new message has been left for the user, either in a personal voice mailbox or in a group mailbox or call back message. When the message has been played or acknowledged, the lamp is turned off. All Avaya digital and IP phones have in-built message waiting lamps. one-X Portal for IP Office and Phone Manager also provide message waiting indication on screen.
For analog phones, from IP Office 3.1 a variety of analog message waiting indication (MWI) methods are provided. Those methods are 51V Stepped, 81V, 101V and Line Reversal. The MWI method must be selected from the IP Office Manager when configuring a system to match the properties of the analog phones. Note that the 101V signaling is only available on IP500 Phone cards and expansion modules plus version 2 IP400 Phone 8, 16 and 30 expansion modules, not on the IP406 V2 control unit.