Time And Date Issues; Display Time And Date Incorrectly; Display Issues; The Phone Screen Is Blank - Yealink SIP-T3 Administrator's Manual

Administrator's Guide for SIP-T2 /T3 /T4 /T5 /CP920 IP Phones
Scenario 2:
Yealink phones support using FTP, TFTP, HTTP, and HTTPS protocols to download configuration files or resource
files. You can use one of these protocols for provisioning.
When provisioning your IP phone obtaining an IPv6 address, the provisioning server should support IPv6 and the
format of the access URL of the provisioning server can be "tftp://[IPv6 address or domain name]". For example, if
the provisioning server address is "2001:250:1801::1", the access URL of the provisioning server can be "tftp://
[2001:250:1801::1]/". For more information on provisioning, refer to

Time and Date Issues

Display time and date incorrectly

Check if the IP phone is configured to obtain the time and date from the NTP server automatically. If your phone is
unable to access the NTP server, configure the time and date manually.

Display Issues

The phone screen is blank

Do one of the following:
Ensure that the IP phone is properly plugged into a functional AC outlet.
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Ensure that the IP phone is plugged into a socket controlled by a switch that is on.
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If the IP phone is plugged into a power strip, try plugging it directly into a wall outlet.
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If your phone is PoE powered, ensure that you are using a PoE-compliant switch or hub.
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The phone displays "No Service"

The LCD screen prompts "No Service" message when there is no available SIP account on the IP phone.
Do one of the following:
Ensure that an account is actively registered on the phone at the path Menu > Status > More > Accounts.
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Ensure that the SIP account parameters have been configured correctly.
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Phone Book Issues

Difference between a remote phone book and a local phone book

A remote phone book is placed on a server, while a local phone book is placed on the IP phone flash. A remote
phone book can be used by everyone that can access the server, while a local phone book can only be used on a
specific phone. A remote phone book is always used as a central phone book for a company; each employee can
load it to obtain real-time data from the same server.

Audio Issues

Increasing or decreasing the volume

Press the volume key to increase or decrease the ringer volume when the IP phone is idle or ringing, or to adjust
the volume of the engaged audio device (handset, speakerphone or headset) when there is an active call in pro-
gress.

Get poor sound quality during a call

If you have poor sound quality/acoustics like intermittent voice, low volume, echo or other noises, the possible reas-
ons could be:
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Yealink SIP IP Phones Auto Provisioning Guide.