IMPORTANT This device has been tested for Fax and Voice using firmware "V1.2.1.5" versions available from: http://www.grandstream.com/firmware.html.

3CX Support shall require use of the above firmware to address support issues. Please note that you must factory reset the device before starting this procedure to reduce the possibilites of encountering difficulties. Note also that the device must be connected to the LAN using the WAN port of the device.

Step 1: Configuring 3CX Phone System to work for use with the Grandstream GXW-4104 / GXW-4108

1. Log on to the 3CX Phone System Management Console and go to: Lines => Add PSTN
2. Assign a name to the Grandstream device: Grandstream_GXW4104
3. Select the device type – in this example we will assume: Grandstream GXW4104
4. Click the "Next >" button.|
   
   
   
   From the "Country" drop-down menu, select the Country Tone Set that most closely matches that in use by the Telecoms Provider supplying the Analog lines.
5. From the "Caller ID Scheme" drop-down menu, select the scheme that matches that in use by the Telecoms Provider supplying the Analog lines.
6. Click the "Next >" button.
   
   
   
   
7. In the field “Gateway Hostname or IP”, insert the IP Address that you would like the device to use when connected to the LAN for communication with 3CX Phone System. This must be a STATIC IP. Note that the gateway device and the 3CX Phone System must reside inside the same LAN. 
8. The “Number of ports” field is set by default to the number of ports available in the device.
9. Click the "Next >" button.
10. The “Create Lines” page allows you to configure each channel’s parameters, namely:
    a. Virtual Extension Number
    b. Authentication ID
    c. Authentication Password
    d. Number of simultaneous calls that the channel can handle
    e. The Port Identification (External Number) of the channel
    f. The destination of calls that are received by the channel - These values are pre-opulated, but may be changed at this point. The configuration file will be generated using the parameters supplied in this page.
11. Click the "Next >" button.
    
    
    
    
12. The "Create Outbound Rule" page provides a quick and easy way to correctly configure a simple rule to allow outbound calls using the gateway device to deliver outbound calls. A simple starting point could be to use "0" as the prefix, and all extensions will be able to dial outbound via this rule. The other values are pre-populated, but may be changed at this point.
13. Click "Finish" (or "Skip" if you do not want to create an outbound rule).
14. The 3CX Phone System is now fully configured for the Grandstream GXW-4104. You can now click the “Generate config file” button (you will need to provide the subnet mask of your LAN) to save to disk a file that will automatically configure the device with the settings provided above.

Step 2: Configuring the Grandstream GXW-4104 / GXW-4108

1. Connect the GrandStream GXW-4104 gateway to the network and main power supply. The device will boot up, using its factory-configured default IP address 192.168.0.160.
2. Now point your browser to the gateway’s configuration site: http://192.168.0.160.
3. Enter the password of the device and click ‘OK’ to access the gateway’s configuration. The default password is “admin”.
   
   
   
   

4. Once the page loads click on the “Profile 1” tab at the top of the page:
   a. Set the “SIP Server” field to the IP Address or FQDN of the server on which 3CX Phone System is installed.
   b. Set the “SIP Registration” field to “yes”.
   c. Click the “Update” button at the bottom of the page.
   
   
   
   

5. Click on the “Channels” tab at the top of the page. In the “Phone Number Settings” table, the rows represent the 4 PSTN lines connected to the gateway. Configure each line as follows:
   a. The “Channel(s)” field should contain the order number for the line. Normally 1 for the first enabled line, 2 for the second enabled line, and so on.
   b. The “SIP User ID” field should match the Internal Line Number field of the line created for this PSTN line in the 3CX Phone System Management Console.
   c. In the “Authenticate ID” and “Authentication Password” fields enter the ID and Password that you entered for the line in the 3CX Phone System Management Console. These fields must match the ID and password set for that line in the 3CX Phone System Management Console.
   d. Click the “Update” button at the bottom of the page.

6. In the same page, you need the configure the Call Progress Tones. By default the unit will ship with US Call Progress Tones. If you are installing the unit outside the US, these Call Progress Tones will likely need to be changed. All you need to do is copy the correct strings into the 5 sections. You will find a a ready string for Call Progress Tones of the main countries here for the GXW 4104 and here for the GXW 4108.  Click the update button when done.
   
    
   
   

7. Click on the "FXO Lines" tab at the top of the page. Configure this page as follows:
   a. Set the “Stage Method” field to "ch1-4:1;"
   b. Set the "Unconditional Call Forward to VOIP" field to: "ch1-4:yyyyy+;" where yyyyy is the SIP User ID for the first line defined in the "Channels" page.
   c. Click the “Update” button at the bottom of the page.
8. Click on the “Reboot” button to restart the device.
9. After the gateway has restarted, switch to the 3CX Phone System Management Console, and go to the "Ports/Trunks Status" page, where the PSTN lines connected to the VoIP Gateway should be listed with a green status light.

Enabling FAX on the GrandStream GXW-4104 Gateway

1. To enable Inbound FAX on the GXW4104 T.38 settings must be enabled for the appropriate FXO channels.
2. Load the gateway’s web interface
3. Click on the “FXO Lines” tab
   
   
   
   
4. Confirm that “T.38 Setting” is enabled to relay on all channels. The settings for GXW4104 should be: "ch1-4:mode=1,rate=9600,ecm=1;" , while the settings for GXW-4108 should be: "ch1-8:mode=1,rate=9600,ecm=1;" – this will set all channels to mode 1 (Relay as opposed to pass-through using PCMU), the baud rate is set to the default 9600, and ECM is set to the default 1 which means that error correction is enabled.
5. If any changes have been submitted click “Update” to apply.

ADDITIONAL NOTES:

When receiving an inbound call on the GXW4104/4108 which is then diverted to an external number via the 3CX configuration, if the GXW4104/8 is used for the diverted call the GXW will stop sending SIP signaling to 3CX. This is a known issue with the GXW. As a workaround, in the 3CX User Interface, edit the Grandstream device, go to the "Advanced" tab, and enable the "PBX delivers audio" option.

Please note that applying this workaround will no longer allow inbound or outbound faxes to be delivered over the Grandstream device – so you will need a separate dedicated device/line for delivering faxes.