Configuring Grandstream GXW Series FXS VoIP Gateway

Supported Models Grandstream GXW4216, GXW4224, GXW4232, GXW4248

FXS gateways connect internal analog devices such as fax machines or analog phones and register them as extensions / fax extensions to your PBX. Those extensions can be addressed as normal phones, however, their functionality is limited due to the capabilities of the analog technology.

Notes:

• Ensure that you have created the extensions, (or fax extensions), before adding the FXS gateway to the PBX.

Step 1: Create Fax extension (Optional)

If the FXS Gateway will be used to connect fax machines to the PBX, the “Fax Extensions” option must be used instead of a regular extension.

1. Go to the 3CX Admin Console.
2. Navigate to Advanced > Fax and select Add.
3. Define the “FAX Extension Number”, the “FAX Extension Authentication ID” and the “FAX Extension Authentication Password”.

Step 2: Add and Choose Device

1. Navigate to Voice & Chat within the 3CX Admin Console and select “Add DECT / FXS”:

2. Select Model/Device: GrandStream GXW4224
3. MAC Address: Enter the “MAC Address” of the Grandstream gateways (Without colons or dashes)
4. Press “Next” to select the provisioning method: choose from “Local LAN/VPN" or “Connect via SBC/ router phone” depending on your setup.

Step 3: Configure the Gateway

If using the GXW Gateway for faxing, choose the fax sending transmission Mode.

• FAX in T.38
• Fax in Audio G711(Pass Through)

Step 4: FXS Line Setup

1. Select the extensions you wish to have configured on this device.
2. Click “Add FXS” to complete the configuration of the Gateway device.

Step 5: Prepare Grandstream FXS Gateway

Make sure that your Grandstream device is factory reset. If not, reset the Grandstream FXS Gateway by pressing and holding the “Reset” button for about 5 seconds.

The Grandstream FXS gateway is configured, by default, to have an IP Address assigned via DHCP. To find out the IP Address defined by the Gateway:

1. In the screen on the front of the device, you should be able to see the IP Address of the device. If you do not see the IP Address, press the DOWN button to show the IP Address while in the Home screen.
2. Connect via your browser to the IP Address mentioned in the steps above
3. Log in to the Gateway, by entering the IP Address shown in the screen of the device, in the browser.

4. The default password is: admin (This will be changed when the device is provisioned)

Step 6: Update the Firmware (If firmware is not the latest)

1. Download the latest firmware from here.

2. Go to the “Maintenance” menu
3. Select “Upgrade and Provisioning”
4. In the “Upload Device Firmware” section click “Upload”
5. Click “Choose File”
6. Navigate to the firmware file
7. Select the relevant firmware file
8. Click “Open”

9. Click “Upload” to apply the firmware to the gateway

After a few minutes, you will be able to log in to the device and start using it again.

Step 7: Upload the configuration to the gateway

1. Edit your “DECT/FXS” you created in the Admin Console.

2. Copy the Provisioning Link to a browser and right click “Save Target as”, to save the configuration file into your disk. This XML file will be the configuration file of your gateway.
3. Log on to the gateway via web browser, using the default username and password, as mentioned above.

6. Go to the “Maintenance” tab
7. Select “Upgrade and Provisioning”
8. In the “Upload Device Configuration” section, click the “Upload” button.
9. Navigate to the XML file you downloaded from the 3CX Admin Console
10. Click “Open”
11. Click “Upload Configuration”

During this time the gateway will apply the configuration and reboot. When the gateway is ready, you will see the IP Address come up on the screen of the device. You will be able to see the normal extensions status in the “Extensions” page of the PBX. If you are using FAX Extensions, you will see the status of these in the “System Extensions” page.

Last Updated

This document was last updated on 10 September 2026

https://www.3cx.com/voip-gateways/grandstream-gxw-fxs/