Yealink VC120, Administrator'S Manual

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Troubleshooting
287
Why doesn’t the display device display time and date correctly?

If you have configured the system to obtain the time and date from the NTP server
automatically, ensure that SNTP server and time zone are configured correctly in the
system and whether the connection between the system and NTP server is working
properly.

If you have configured the system to obtain the time and date manually, ensure that you
have configured the time and date correctly.
Why doesn’t the remote control work?

Check whether the system is powered on.

Check whether the positive and negative charges of the battery are connected correctly.

Check whether the battery has sufficient power left.

Check whether no special fluorescent or neon signs nearby.
Why does the system fail to call the far site?

Check whether the network of the local site is available.

Check whether the network of the far site is available.

Check whether the far site enables the DND feature.

Check whether the accounts have been registered correctly, and the system uses the
appropriate account to call the far site.

Ensure that the number you are calling is correct.

Check whether the far site rejects your call.

Check whether the firewall blocks the inbound traffics from the other site.

Check whether the far site has already up to maximum call-in limitation.

If the local site is forced to use encryption, ensure that the far site enables encryption too.
For more information on call encryption, refer to
Secure Real-Time Transport Protocol on
page 259 and H.235 on page 263 .

Ensure the far site supports the same call protocol as the local site.
Why does the system fail to call the far site via IP address?

Ensure that at least one call protocol is enabled on both sites. For more information, refer
to
Configuring SIP Settings on page 126 and Configuring H.323 Settings on page 130.

Ensure that the network is connected correctly.

Ensure that the network is configured correctly. For more information, refer to Configuring
LAN Properties on page 48 .

Ping the IP address of the far site. Contact your system administrator if it fails. For more
information, refer to
Using Diagnostic Methods on page 284 .