Notice for using MiiTel

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

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

If you will be using MiiTel Phone Mobile, please read Confirmation before using MiiiTel Phone Mobile.

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 you have 10 people talking at the same time, 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 voice communications, we recommend that you prepare the internet network with a margin of approximately three times the required bandwidth. The following is a guideline of the network quality so 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 443/tcp port for voice communication. If possible, we recommend users to 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 setup the destination IP address, please contact Support.
  • If you are not sure of setting up, please 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 to use wired LAN.
  • If 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 automatically stop. To avoid this problem, please prepare a product with a good amount of capacity. Also, for products that can set the refresh frequency, please set with enough 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.
  • When using wireless LAN, if the communication quality is not stable, please 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 make the signal strength stronger.
    • Avoid using the Wi-Fi tethering feature of smartphones or portable Wi-Fi routers in the office.
    • Replace access points that are 4 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. Please set the router to bridge mode or change the logical network so that NAT is not performed more than once.

  • Please also 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 communications.

  • If you have no choice but to use a proxy server, please make sure that your calls to MiiTel are not routed through the proxy server as shown in the picture below. Also if possible, include the domain in the whitelist that is used to communicate with MiiTel, and test your calls beforehand to make sure there are no voice quality issues. 


    • The domain we recommend to include in the whitelist for MiiTel:
      • https://*
      • https://*
  • The following products have been reported to inadvertently block voice communications in some cases, but you can make calls smoothly by including the communication address to MiiTel, in the whitelist.

    • Trendmicro InterScan Web Security

Using thin client, remote desktop, or VDI environments

  • This feature may not work properly depending on the product used and the setting conditions. Please make sure that the microphone and speakers are functioning properly before use. If you have any questions, please contact us at Support.

3. Recommended computer environment

  • The following are the recommended computer OS and browsers for using MiiTel Phone, MiiTel Analytics, and MiiTel Live.
    • OS : Windows 10, Windows 11 (Requirement for MiiTel Phone Desktop is 64bit OS)
               macOS (El Capitan or later. Apple Silicon is incompatible.)
    • Browser : Latest version of Google Chrome / Microsoft Edge version 49 or later
  • Voice calls may get affected if your computer is overloaded. In particular, if any of the following cases apply to you, please turn off the application or refrain from using multiple applications 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
  • We received a report that some users cannot log in properly when using the following Google Chrome extensions. Please add the MiiTel URL to your whitelist or uninstall the extension.
    • Ghostery (Blocking of Web Tracking Ads)

4. Headset

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

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