Yealink VC400, Administrator'S Manual

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Administrator’s Guide for Yealink Video Conferencing Systems
268

Check whether the far site has already up to maximum call-in limitation.

If the near 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 239 and H.235 on page 243 .

Ensure the far site supports the same call protocol as the near 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 122 and Configuring H.323 Settings on page 126 .

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 264 .
Why doesn’t the status bar of the display device display IP address?

Check whether the network is available.

Check whether the LAN property is configured correctly. For more information on LAN
property configuration, refer to
Configuring LAN Properties on page 48 .

Check whether the system has enabled the hide IP address feature. For more information
on disabling the hide IP address feature, refer to
Hide IP Address on page 165 .

Check whether the system has configured firewall and NAT correctly. For more information
on, refer to
Configuring the System for Use with a Firewall or NAT on page 77 .
Why does the network keep losing packets?

Check whether the network is available and the LED indicator on the left of the Internet
port illuminates green.

Try to use the low speed connection to check whether packets are lost. Deficient
bandwidth is an important reason for packet loss.

Check the configuration of the network speed and duplex mode on the system, switch and
router.
Camera Issues
Why can’t I adjust the camera angle and focus?

You can adjust the camera when the system is idle or during a call. The camera cannot be
adjusted when the system is in the menu screen.

Ensure that the batteries in the remote control are in good working condition, and