Yealink SIP-T54S, Administrator'S Manual

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Troubleshooting
991

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.
Why does the IP phone display “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
What is the 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 by 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
How to increase or decrease 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.
Why do I 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.

Intermittent voice is mainly caused by packet loss, due to network congestion, and jitter,
due to message recombination of transmission or receiving equipment (e.g., timeout
handling, retransmission mechanism, buffer under run).

Noisy equipment, such as a computer or a fan, may cause voice interference. Turn off any
noisy equipment.

Line issues can also cause this problem; disconnect the old line and redial the call to