IP PBX’s continue to grow in popularity but the main cost point has continued to be the interface device to the telephone company’s circuits and internal PCI cards suffer from IRQ conflicts and also don’t work with machine virtualization. External SIP gateways have been expensive and difficult to setup. Grandstream has always been leader in innovation and providing products at really good prices. Anyone that has used their ATA’s know that they ‘just work’ and are rock solid, not to mention very cost effective. So did Grandstream really deliver with the GXW-4104/GXW-4108 SIP Gateways? Your going to have to read our review to find out.

The GXW-4104 is a slick looking box that is certainly one of the best looking products to ever have come out of Grandstream’s engineering department. We wanted to put the GXW-4104 to the test so we decided to put it to use in a production environment in a small business using a trixbox server. First, lets take a look at what’s inside the box.

Features
The GXW-410x is a voice and video gateway that provides a SIP trunk to an IP PBX such as Asterisk, SIPx, OpenPBX, or other compatible systems. The gateway series includes the GXW-4104 (4-port) and GXW-4108 (8-port) models. These units convert a standard POTS (analog) phone line into a VoIP trunk delivered to your IP PBX. The video surveillance port enables remote security monitoring.

• 4 and 8 port media gateways
• Video surveillance port
• Two RJ-45 ports
• Multiple SIP accounts and profiles
• Audio Codecs: G.711, G.723, G.729, GSM, G.726, G.168
• Real time H.264 video codec
• T.38 Fax
• Echo Cancellation
• Dynamic jitter buffer

Setup
My first real gripe with the box is the setup procedure. Every other device I can think of defaults to using DHCP so you can toss it on the network and get up and running as well as use tFTP servers for automated provisioning. Instead, the factory default setting is to have the IP address of the device set to 192.168.0.160 which means you have to tweak your IP address settings to be able to access the unit unless you are already running on that network block.

Once I logged into the web interface the first time I manually set the IP address and related network settings and rebooted. Next we set it up to work with our trixbox platform.

Under the FXO Lines tab you want to change the Stage Method and the Offhook Auto Dial settings. Set the following fields as shown here:

Stage Method (1/2): ch1-4:1;
Offhook Auto Dial (VoIP): ch1-4;xxxxxxxxxx;
(Set xxxxxxxxxx to your phone number for routing within FreePBX)

Select Update and reboot the device. Double check the settings and make sure they are saved, there are a few quirky issues with saving settings sometimes so always double-check to see if it was actually saved.

On the Channels tab there is only one setting you should change here and it is the setting for DTMF type. The default for an Asterisk-based system is RFC2833 so the setting we want is as follows:

DTMF Methods: ch1-4:2;

Again, save your changes and then reboot and like before, double check to make sure the settings are actually saved properly. Hopefully this bug will be fixed in a current firmware version and will work as reliably as other Grandstream products we are used to using.

The final settings are under the Profile 1 tab. Here you want to set the SIP server, registration and NAT options as follows:

SIP Server: set to IP address of your PBX
SIP Registration: No
NAT Traversal: No

For the last time, select Update and reboot and double check all the settings to be sure they are all saved.

All you need to do in FreePBX is to create a SIP trunk. Since we have registration turned off we only need to setup an outgoing trunk so long as you have “allow anonymous sip calls” turned on in the General Settings.

Trunk Name: Grandstream

PEER Details:
context=from-trunk
host=<ip address of PBX>
insecure=port
type=peer

Save your settings and click on the red apply bar.

Under your inbound routes make sure you either have a blank (no cid/no did) route or one with the DID set to the phone number you used during the GXW-410x setup routed to a destination. Then go to Outbound Routes and make sure you have an outbound route setup to use the Grandstream trunk.

Once everything is saved and the red apply bar is clicked, you should be working.

Results
Other than the quirky IP address setup, the reset of the device setup was very simple and fairly straightforward. On my particular line, the receive volume was a bit low so I went back into the settings on the device to crank up the RX Gain a few notches. This resulted in another bout with the wonky firmware saving feature, but a few tries got everything saved and working.

The sound quality is as good as the Linksys SPA-3000/SPA-3102/SPA-400 devices. I have never had echo on my lines with the Linksys so I can’t really say if the GXW-410x devices are any better or worse as I had no echo problems at all.

With a street price of around $279, it is the most affordable 4-port SIP gateway available. I’m not sure how useful the video surveillance option is and it is not well documented. If I can find some video source for it I will give that feature a whirl. In the meantime, the GXW-4104 is an excellent value and performs quite nicely for a unit at this price.