Setting up a Grandstream GXW-4104 or 4108 to integrate POTS lines to a Protel PBX

Setting up a Grandstream GXW-4104 or 4108 to integrate POTS lines to a Protel PBX

Protel LTS premise PBX systems are not manufactured with analog telephone ports built in to the PBX I/O, though we do offer built-in PRI capability as an optional add-on.    If you want to connect standard legacy telephone lines (POTS) to a Protel PBX and be able to send and/or receive phone calls on those analog lines, you will need an additional device called an FXO Gateway.  nexMatrix recommends using the Grandstream GXW-4104 (4 analog line ports) or GXW-4108 (8 ports) for this purpose.  The Trunks section of the Protel PBX administration interface has a standard preset that allows you to integrate one or more Grandstream FXO units without having to add any trunk customization to the PBX.  Gateway products from other manufacturers can also be integrated, by using the Custom Trunk configuration tool in the PBX, but nexMatrix may not be able to fully support your efforts with those devices.
This article will provide detailed instructions on how to set up and configure a Grandstream GXW-41xx FXO and integrate it with a Protel PBX.

1. Assess the logistical requirements. 
It is a good practice to decide the best placement for the FXO unit prior to showing up on site with it.  The FXO device requires a single wired network connection, so the location and availability of network switch ports are important considerations when deciding where to place it.  The location of the Telco demarc may also influence your decision, since those phone lines have to connect to the FXO on individual modular (RJ-11) ports.  The Grandstream unit will not run from PoE (Power Over Ethernet) unlike most IP telephones, so you also have to consider the location of the nearest available AC outlet.

2. Identify and tag each phone line. 
Decide ahead of time how your Telco lines will be utilized.  One common scenario is for the Telco to deliver inbound service on two or more POTS lines in a "Rollover" configuration.  If the primary published customer phone line is engaged on a call, the next incoming call will roll over and ring the next available idle line in the rollover sequence, repeating that behavior until all of the available rollover lines are engaged. There may also be phone lines with DID numbers that are not grouped in the rollover, such as direct dial numbers to individual extensions, or numbers handling calls for specific departments or even separate businesses housed in the same facility.  You will need to be able to physically identify each Telco pair in the phone closet or demarc location and you need to have a solid understanding of how incoming calls on each of those lines need to be handled.  Having all of your homework done will make device configuration much easier and save you from having to do things multiple times because of incomplete or erroneous information.

3. Assign a Static IP address to the Gateway
Just like the Protel PBX, the FXO Gateway requires a static IP address on the LAN.  If the gateway is co-located with the PBX, there are no port forwarding requirements, but you will need to log into the LAN router when you first set it up to be able to identify the DHCP address that it acquired.  Make sure the address you assign to the FXO is outside the DHCP range of the router and that there is no possibility of IP conflict with some other device. 

4. Log into the Gateway's web interface and change the network settings. 
Power up the FXO and connect a network cable between its WAN port and an available port on the local network.  In the LAN router's web interface, locate the page that displays devices that are currently connected.  You may need to reference the MAC address of the FXO if the router does not display host names.  Enter that LAN address into a web browser (the computer has to be connected to the same network as the FXO) and log in with the default pasword of "admin".  Navigate to the Networks tab and change the settings from DHCP to Static.  In this example, the FXO has a static address of

The Google public DNS server should be adequate (  If you have the preferred DNS addresses for the ISP available, you can enter one of those as the secondary.  Click on the Save button and confirm that you want to reboot the device.  These units boot quickly so you should be able to log into it again at its static address in about 15 seconds.  NOTE:  after each of the remaining steps, the FXO will prompt you to reboot after saving new settings.  You can safely bypass that and wait until you have completed and saved all of your settings before rebooting.
4. Configure the Account settings.
On the General Settings page of Account 1, enter the IP address of the Protel PBX and an optional name.  Leave the Proxy field blank.

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