Message waiting indicator (mwi) – Yealink SIP-T20 User Manual
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Advanced Phone Features
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or to dial out the voice mail access code.
2. Follow the voice prompt to listen to voice mails.
Note
To view voice mails via phone user interface:
1. Press .
2. Select Messages->View Voice Mail.
The LCD screen displays the amount of new and old voice mails.
 
 
 
 
 
3. Select an account and then press to listen to voice mails.
The SIP-T20P/SIP-T20 IP phone supports MWI when receiving a new voice message. If 
someone leaves you a voice mail, you will receive a message waiting indicator. MWI 
will be indicated in three ways: a warning tone, an prompt message (including a voice 
mail icon) on the LCD screen, and the MESSAGE key LED illuminates solid green. This 
will be cleared when you retrieve all voice mails or delete them. 
The MWI service is unsolicited for some servers, so the SIP-T20P/SIP-T20 IP phone only 
handles the MWI messages sent from the server. But for other servers, the MWI service 
is solicited, so the SIP-T20P/SIP-T20 IP phone must enable subscription for MWI. 
Note
The MWI Subscription parameters you need to know:
Option
Description
Subscribe for MWI
Enable or disable a subscription for MWI service.
MWI Subscription 
Period 
Period of MWI subscription. The IP phone sends a refresh 
SUBSCRIBE request before initial SUBSCRIBE expiration. 
Subscribe MWI to 
Voice Mail 
Enable or disable a subscription to the voice mail number 
for MWI service. To use this feature, you should configure 
MWI service is not available on all servers. Contact your system administrator for more
information.
1. 1234
2 new 1 old Mail
Before listening to the voice mails, make sure the voice mail access code has been 
configured. 
When all new voice mails are retrieved, the MESSAGE key LED will go out. 
 
