Yealink T48G, Administrator'S Manual

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Troubleshooting
579
Display Issues
The phone LCD screen blank
Do one of the following:

Ensure that the IP phone is properly plugged into a functional AC outlet.

Ensure that the IP phone is plugged into a socket controlled by a switch that is on.

If the IP phone is plugged into a power strip, try plugging it directly into a wall outlet.

If your phone is PoE powered, ensure that you are using a PoE-compliant switch or hub.
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 IP phone at the path
Menu->Status->More->Accounts.

Ensure that the SIP account parameters have been configured correctly.
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 the 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 engaged audio device (handset, speakerphone or headset) when there is an active
call in progress.
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 reasons could be:

Users are seated too far out of recommended microphone range and sound faint, or are seated too
close to sensitive microphones and cause echo.