Notice for using MiiTel

MiiTel is an IP phone that requires an internet connection to make calls.

Please refer to the following to prepare the network environment to use MiiTel smoothly.


1. Internet connection and router

Preparing your internet network

  • MiiTel requires a stable internet connection for voice communication. During a voice call, MiiTel will use approximately 100 kbps. For example, if ten people are talking simultaneously, the speed will be about 1 Mbps.
  • If the bandwidth reaches its maximum capacity, packet loss may occur, and the sound quality might decrease. Considering the occurrence of communications other than the voice, we recommend that you prepare the internet network with a margin of approximately three times the required bandwidth. The following is a guideline for network quality so that you can make your calls smoothly.

Guidelines for the Internet connection you should prepare

Category Value (Approx.)
Network Speed

1 user: at least 300 kbps

Average Response Time

100 milliseconds or less


30 milliseconds or less

Packet Loss

1 % or less

The numbers above can be measured by running MiiTel Speed Test.

Router settings

  • MiiTel uses the 443/tcp port for voice communication. If possible, we recommend users add QoS settings for better voice quality.
  • If users can add QoS settings, they will be able to use TCP or UDP ports, but using ports other than 443/tcp is not mandatory.
  • For customers that need to set up the destination IP address, contact Support.
  • If you are not sure about the settings, contact the vendor who installed the network equipment.

2. LAN configuration in the office

Things to check when using the wireless LAN

  • Compared to wireless LAN (Wi-Fi), wired LAN is more resistant to network congestion in office LANs and is less affected by radio wave conditions, so we recommend customers use wired LAN.
  • If the NAT table gets refreshed during the call, it may cause to have some parts of the call to be cut or the phone call itself to stop automatically. To avoid this problem, prepare a product with a good amount of capacity. If you are using products that can set the refresh rate, set the rate with plenty of time. 
  • Please note that an environment where the private IP address is frequently changed due to switching access points may also deal with the same problems for phone calls.
  • If the network is not stable when using wireless LAN, check the following points below.
    • Connect both the computer and access point with compatible devices of IEEE 802.11ac or better. 
    • In areas where the signal strength is weak, install additional access points to strengthen the signal strength.
    • Avoid using the Wi-Fi tethering feature of smartphones or portable Wi-Fi routers in the office.
    • Replace access points that are four years or older with new equipment.

Eliminate Double NAT

  • A configuration in which additional routers are placed under the router may result in Double NAT. Configuration settings like Double NAT, may interfere with voice communications. Set the router to bridge mode or change the logical network so that NAT will not perform more than once.

  • Also, please note that Wi-Fi access points added to the LAN may operate as NAT routers.


Using a proxy, L7-firewall, and web-filtering products

  • We recommend that you do not use proxy servers (including products called L7-firewalls and web-filtering), as they can cause delays in voice communication.

  • If you have no choice but to use a proxy server, make sure that your calls to MiiTel are not routed through the proxy server, as shown in the picture below. If possible, include the following domains in the whitelist, and test your calls beforehand to ensure there are no voice quality issues. 


    • The domains we recommend including in the whitelist for MiiTel:
      • https://*
      • https://*

Using thin client, remote desktop, or VDI environments

  • Please note that depending on the product or the settings, you might not be able to use this feature properly. Also, check if your microphone and speakers are working properly you use this feature. If you have any questions, please contact us.

3. Recommended computer environment

  • The following are the recommended computer OS and browsers for using MiiTel.
    • OS
      • Windows 10, Windows 11 (Requirement for MiiTel Phone Desktop is 64bit OS)
      • macOS 10.11 (El Capitan) and above
      • ChromeOS latest version
    • Browse
      • Latest version of Google Chrome
      • Latest version of Microsoft Edge
  • Voice calls may get affected if your computer gets overloaded. In particular, if any of the following cases apply to you, turn off the app or refrain from using multiple apps at the same time. 
    • Windows Update or Anti-virus software scanning.
    • Using software that involves a lot of 3D drawings.
    • Opening a large number of browser tabs or a large number of Add-ons are running.


4. Headset

  • We recommend you use a USB-connected headset (both ears). Earphone microphones and built-in PC microphones tend to pick up surrounding sounds, so we recommend you use a USB-connected headset (Logicool) with a noise-canceling feature. (This headset costs around 2,000 to 3,000 JPY.)

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