Device information - Yealink WF40 USB Wi-Fi Dongle

Important: at this time the Yealink WF40 Wi-Fi USB Dongle is not sold or supported by Intermedia. This article is made available as a guide to assist in using this equipment. Intermedia cannot currently warranty replace phones experiencing issues with this device.

The WF40 is a cost-effective solution for SOHO (small office, home office) customers that offers an extremely simple way to connect Yealink IP phones to an organization’s current wireless network. The device is a small USB dongle that plugs into the back of a Yealink T46G or T48G desk phone and allows customers to search for their SSID (or manually enter it) and type in their Password using the phone’s keypad.

Intermedia has tested this solution and validated the product. 

Requirements for using the WF40

The following hardware is required to utilize this Wi-Fi solution:

  1. An existing Wi-Fi enabled network
    • The Wi-Fi transmitter will need to support the 2.4 GHz frequency
    • The Wi-Fi transmitter must support either WPA-PSK or WPA2-PSK encryption

  2. Yealink Wi-Fi USB dongle(s), model WF40

  3. Yealink brand desk phone(s) with USB Wi-Fi dongle support

The following Yealink phones are capable of supporting the USB Wi-Fi dongles:

  • Yealink T46G 16-line phone 
  • Yealink T48G 20-line phone 
  • Yealink T42S 12-line phone 
  • Yealink T46S 16-line phone

When purchased directly from Intermedia, the phones are already loaded with the correct firmware to utilize the USB dongle. 

Anyphone BYOP customers that wish to use the WF40 device will have to ensure they have the correct official Yealink FW update for their phones:

  • Yealink T46G 16-line phone upgraded to FW version x.81.0.110 or higher.
  • Yealink T48G 20-line phone upgraded to FW version of or higher

Obtaining a WF40

Intermediadoes not sell the WF40.  The device is widely available from major online retailers such as Voipsupply, Amazon, or New Egg. Retail price is around $30.00 each.

Connecting Phones via the WF40

Installation of the WF40 dongle is as simple as connecting a cell phone to the current Wireless network. 

Before setting up wireless, it is important to note that the IP phone ONLY has the power adapter connected; NO Ethernet cable (either wired Ethernet or Ethernet over Power) should be connected as this will automatically disable the Wi-Fi functionality on the Yealink T4x phone and the user will not be able to configure their wireless network information on the device.

You will also need to know both your SSID (Wi-Fi Network Name) & Wireless Password/Key. 

Important: when connecting the phone to the Internet for the first time kindly connect the device via Ethernet cable so it could provision correctly. Due to the number of reboots that occur during provisioning, it has been found to be more beneficial to provision the phone using an ethernet connection rather than wireless. The device can be moved to wireless after it has completed, this is just temporary to complete the initial provisioning without an error occurring.

Note: the Wi-Fi password encryption on the Wi-Fi router must be either set to WPA-PSK or WPA2-PSK, in order for the Wi-Fi dongle to connect to the secured network.

To Install and connect to a Wireless Network:

  1. Insert the Wi-Fi USB Dongle WF40 into the USB port on the back of the phone when the phone is in the idle state. The touch screen will prompt: Wi-Fi adapter connected. Scan for available Wi-Fi networks?

  2. Tap the OK button. The IP phone will toggle the Wi-Fi to on and search for available wireless networks in your area.
    • When the scan is completed, you will see a Scan soft key on the screen; this can be pressed to re-scan available Wi-Fi networks.

  3. Use the arrow keys to navigate to the desired wireless network (SSID) on the screen to connect to it, and press the OK button.

  4. If the network is secure, you will receive a Wi-Fi Password field to enter the password/key; enter the password here.

  5. Once the connection has completed successfully, the prompt Connected Successfully appears at the end of the desired SSID.

Disabling Wi-Fi Feature on the IP Phone:

To disable Wi-Fi feature, do one of the following

  1. Tap > Basic >Wi-Fi. Mark the Off radio box in the Wi-Fi field.

Troubleshooting steps for the WF40

  1. Connectivity Issues – Phone doesn’t recognize dongle, Wi-Fi network not displayed, Wi-Fi fails to connect.

    • Verify using on T46G or S  or T48G or S

    • If using Anyphone BYOP, verify Yealink phone firmware is:
      • x.81.0.110 or higher for T46G
      • or higher for T48G.

    • Verify SSID broadcast is on in the router, DHCP is on, and there are enough IP addresses in the DHCP range.

    • Verify the router is handling DHCP on WiFi properly. On some routers DHCP on WiFi will not give out IP addresses to the devices with the same names. This has been a known issue on Verizon Fios Quantum Gateway Wi-Fi Router FIOS-G1100.
    • Verify wireless network is 2.4GHz with WPA-PSK or WPA2-PSK and using 802.11b/g/n.
    • Confirm distance between dongle and Wi-Fi transmitter is less than 150ft and not a lot of walls, x-ray machines, microwaves, large electronic devices in between them.

  2. QoS Issues - Choppy Audio, audio loss, distrotion or noise.
    • Confirm distance between dongle and Wi-Fi transmitter is less than 150ft and not a lot of walls/x-ray machines/large electronic devices in between them.

    • Run a wi-fi analyzer/scanner on a smartphone or a laptop to find the channel with the least interference from other nearby access points, then change your access point's Wi-Fi channel to that.
    • Routers with certain firmware sometimes have a built-in Wi-Fi scanner or analyzer, such as Asuswrt-Merlin firmware, though they often can only operate either as access point or as a scanner.


Temporary Resolution for the WF50 on T4xS series phones:

Note: the official firmware that we are currently testing with the WF50 dongle is

While we are still testing this official firmware, a known-working firmware version can be downloaded to resolve issues with the WF50 dongle. 

Since the version is not custom-made for us by Yealink, unlike the official version, it may cause issues with your current configuration.
If you accept the risk, here are the steps for downloading the version

    1.    Obtain a firmware from Yealink here. The latest firmware has been confirmed to work with both WF40 and WF50 dongles.
        a.    Look for the device that corresponds to what your customer has and click on it.
        b.    Download the latest .rom file. This is usually annotated with the following of “New”
    2.    Open a remote session and log into the customer's phone.
    3.    Navigate to Settings > Upgrade> Select and Upgrade Firmware
        a.    Choose the file and click on the Upgrade button.
    4.    Wait for the firmware upgrade to complete and then install the WF50.

Generic SIP phones, phones that are not utilizing our enhanced provisioning servers are not impacted by this.

This workaround is only valid for Yealink T4xS series phones with a USB port.

If you are not sure of your phone's capability, please check the Yealink phone comparison guides by clicking here.

Obtaining a WF50

Intermedia does not sell the WF50.  The device is widely available from major online retailers such as Voipsupply, Amazon, or New Egg. Retail price is around $30.00 each.