If you experience issues with voice quality during a call, please check the following.

1. Check the network load

• a. Try a different network from the one you are currently using
  • For example, wired LAN, wireless LAN (Wi-Fi), etc.
• b. Run a speed test to check whether the network quality meets the recommended internet connection requirements
  • Compare the results when the issue occurs and when it does not occur
  • If network access has increased due to more staff, etc., a bandwidth issue may also be the cause

2. Check the computer's load

• a. If you have many applications open, close the ones you do not need
• b. If you have many browser tabs open, close the ones you do not need
• c. Check whether any application other than MiiTel is communicating over the network
  • If it is, check whether stopping it improves the voice quality
• d. Check whether you are running any processes that place a heavy load on your computer
  • Check whether any process is running in the background

3. Check the browser version

• Check whether the browser you are using is up to date
  • If it is not, update it to the latest version

4. Check the headset

a. For wired connections

• 1: Try replacing it with a different headset to see if the issue improves
  • In some customer cases, the issue was caused by a faulty earphone
• 2: Without using the headset, try the computer's built-in speaker and mic

• 3: Check the connection between the computer and the headset for wear or damage
• 4: Unplug and reconnect the headset
  • If there was a voice issue during a call, unplugging and reconnecting the headset may resolve it

b. For wireless (Bluetooth) connections

• 1: Try replacing it with a different headset to see if the issue improves
  • In some customer cases, the issue was caused by a faulty earphone
• 2: Without using the headset, try the computer's built-in speaker and mic

• 3: Disconnect any other Bluetooth devices that may be causing interference
• 4: Try a wired headset

5. Check the network status

a. Check the router and other network equipment

• 1: Unplug the router and reconnect it
• 2: If the router's power is connected through a power strip, connect it directly to a wall outlet
  • Insufficient power supply to the router can cause unstable operation
• 3: Avoid a congested router and connect to a different one
• 4: Check whether the NAT table capacity is insufficient
• 5: Check whether there is enough room in the number of NAT sessions
  • This helps prevent the NAT table from refreshing too frequently
• 6: If you have multiple routers, check whether double NAT is occurring
• 7: Check whether QoS settings are available through your router or other network equipment, such as a UTM

b. Check the VPN connection

• 1: Check whether the VPN connection is being turned ON/OFF during a call
  • Switching the VPN connection during a call may affect the call
• 2: Check whether the VPN connection is unstable
• 3: In MiiTel Phone, configure voice communication during calls to bypass the VPN (turn off the VPN) and check whether the voice quality improves

c. Try enabling the setting to force the use of TCP port 443

• In MiiTel Phone, enable the setting to force the use of TCP port 443 and check whether the voice quality improves

6. Check the MiiTel Phone mic settings

First, open the MiiTel Phone audio settings screen by following the steps below.

1. Launch MiiTel Phone.
2. Click [Menu] > [Settings] > [Audio].
3. The speaker and mic settings will be displayed.
   
   

For the mic settings, change them in the following order and check whether the voice quality improves.

• Uncheck item 1 and check
• Uncheck items 1 and 2 and check.
  • If echo is a concern, uncheck only item 2 and check
• Uncheck items 1, 2, and 3 and check
  • If echo is a concern, uncheck only items 2 and 3 and check
  • If noise is a concern, uncheck only items 1 and 3 and check
  • If both echo and noise are a concern, uncheck only item 3 and check

7. If the user's voice stops reaching the other party during a call

Placing the call on hold and then resuming it may restore the connection.