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Vimal K V
Cisco Employee
Cisco Employee

What is a MWI ?


An MWI is a lamp, flashing LCD panel, or special dial tone on user phones that lets users know a voice message is waiting.The type of indicator depends on the phone system and the user phones.

For Example, Phone systems that support message counts may also display the number of messages that the user has.

Note::   MWIs are NOT the same as message notification, which is the feature that notifies a user of new voice messages by calling a phone, pager, or other device, or by sending an email message.


Events that can trigger Cisco Unity Connection to turn MWIs ON and OFF:


 1. When a message for a user arrives on the Cisco Unity Connection, it notifies the phone system to turn ON an MWI on the phone for that user.

++ Note:: Any message that arrives on the Connection message store (for example, voice messages, emails, and faxes) trigger turning MWIs ON and OFF.

2. When the user listens to the message, Unity Connection notifies the phone system to turn OFF the MWI on the phone.

3. When the user saves a ‘listened-to’ message as a ‘new message’, Connection notifies the phone system to turn ON the MWI on the phone for that user.

4. When a user deletes a new message without listening to it, Connection notifies the phone system to turn OFF the MWI on the phone.

++ Note:: When MWIs are synchronized, Connection queries the message store to determine the status of MWIs on all phones, and resets the applicable MWIs.


An MWI remains ON under the following conditions:


++ Conditions in which more messages are waiting to be heard. (When all new messages are listened to, the MWI is turned OFF)

++ A new message arrives while the user is listening to the original message.

++ The user listens on the phone to only part of the message, and then either hangs up or skips to the next message before hearing the entire message.

++ In an email application or in Cisco Unity Inbox, the user marks a ‘listened-to’ message as ‘unread’.


Note:: Messages in an external message store do not trigger Connection to turn MWIs ON and OFF.


Running the Check Telephony Configuration Test


Step 1 In Cisco Unity Connection Administration, in the Related Links list in the upper right corner of any Telephony Integrations page, click Check Telephony Configuration and click Go.

If the test is not successful, the Task Execution Results displays one or more messages with troubleshooting steps. After correcting the problems, run the test again.

Step 2 In the Task Execution Results window, click Close.



Determining the MWI Port Activity

++ Do the following procedure to generate a report with which you can evaluate the activity of your MWI ports.

Step 1 In Cisco Unity Connection Serviceability, on the Tools menu, click Reports.

Step 2 On the Serviceability Reports page, click Port Activity Report.

Step 3 On the Port Activity Report page, select the applicable options for the report.

Step 4 Click Generate Report.


Synchronizing MWIs


++ To Synchronize MWIs for a Phone System Integration

Step 1 In Cisco Unity Connection Administration, expand Telephony Integrations, and then click Phone System.

Step 2 On the Search Phone Systems page, click the name of the phone system for which you want to synchronize all MWIs.

Step 3 On the Phone System Basics page, under Message Waiting Indicators, click Run.


++ Note:: Synchronizing MWIs for the phone system may affect system performance. Cisco recommends that you do this task when phone traffic is light.


Traces in Cisco Unity Connection


++ Diagnostic traces can be used as a tool to assist you in troubleshooting problems.

++ In Cisco Unity Connection Serviceability, you enable traces to troubleshoot Cisco Unity Connection components.

++ In Cisco Unified Serviceability, you enable traces to troubleshoot services that are supported in Cisco Unified Serviceability.

After the traces are enabled, you can access the trace log files by using Real-Time Monitoring Tool (RTMT) or the command line interface (CLI).


Cisco Unity Connection Serviceability micro traces

Used to troubleshoot problems with specific Cisco Unity Connection components.

Cisco Unity Connection Serviceability macro traces

Used to troubleshoot general areas of Cisco Unity Connection functionality.


Aman Soi
VIP Alumni
VIP Alumni

Good DOC.




Mike Lydick
Level 1
Level 1

A great follow up would be if you expand this to explain the differences between SIP and SCCP mwi signaling events from a Callmanger perspective. Other avenues to explain would be MWI over QSIG trunks.

There is a lot of miss-conception that MWI extension are required to activate the light or that dialing the MWI extension can be used to test MWI. 

Explaining how SIP integration (CUCM to CUC) uses messaging built in the SIP protocol to activate the light on SIP phones where as the SCCP protocol uses SCCP stimulus event from the MWI extension to activate the light on SCCP phones would be insightful.


Vimal K V
Cisco Employee
Cisco Employee

Hi Aman.


Thanking you for going through and commenting on this document.


Regards, VKV

Vimal K V
Cisco Employee
Cisco Employee

Hi Mike,



Thank you for the feedback.

I wish to inform you that I wrote the doc specifically under CUC point of view for the beginners to do a sanity check before approaching TAC .

SCCP and SIP signalling is out of scope of this document even-though MWI works through them.


++ MWI for SIP can be found here.

++ CUCM SIP integration with CUC can be found here.

++ Basic concept of SIP and QSIG MWI can be found here.


++ SCCP is becoming more and more obsolete ( not technologically, but by usage and application ) now a days and I ignore it as of now.



Regards, VKV


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