The GXW series offers a cost-effective, easy to deploy VoIP FXO/FXS analog gateways. The GXW4108 is an analog gateway equipped with 8 FXO ports. Each of these eight ports can take the signal of an analog fixed line. Actually Grandstream offers even more. The GXW4108 is equipped with two Ethernet (RJ-45) ports so you will be able to use the device as a switch. According to Grandstream, the device is T.38 compliant, so you will be able to send and receive faxes through it. It supports various Audio Codecs as G711, G723, G729 and GSM. The firmware can be updated by TFTP or HTTP so you will be able to update it whenever you want. The device even has video surveillance capabilities (a video input port).
The configuration of the device is fairly easy once you get the basics. Grandstream have left the default administrative password (it is `admin`) so I met no problems with this. The network configuration is very simple and easy which grants credit to Grandstream. The next step in my configuration was the setting up the profiles. I had no serious problems again. Everything that should be placed under the Profiles configuration page is exactly there. Without much trouble the SIP server settings were configured. Anyway Grandstream have left eight slots for Audio Codec choice but the device supports only five Codecs. This didn't result into a problem. Then I had to configure the channels. Every channel should register with its own SIP account, and can use one of the three Profiles. The channels support audio gain, which can be separately configured for every single channel.
Unfortunately I have detected some very unpleasant bugs with the GXW4108. The device doesn't always reboot properly. In fact, it just doesn't reboot. I don't know what provokes such behavior but if the device doesn't reboot properly, the only way to reboot it (and load the new settings) is through the hardware key on the back of the device. The other problem is connected with the One Stage Dialing. If you dial from the PSTN the number of the device and you haven't configured the Offhook Dial setting you will hear Ringing but nothing will happen. Of course, if you set the Offhook Dial setting, the device will dial the `offhook` setting on your Asterisk server. I wasn't able to configure the video surveillance capabilities. I've done everything described into the documentation but my vlc player didn't play anything. Anyway, I don't think that video surveillance is a function that should be placed on your analog telephone gateway. Once I installed the device, the audio quality was quite bad, but after a firmware update (to 1.41) this problem disappeared.
This device has the incredible capability to take the place of the Analog Interface Cards such as the Wildcard TDM400p. You can set a limited count of TDM400 into your Asterisk server, but there is no limit over the amount of the GXW4108 that you are using. The low price (approximately 450$) of the device makes it even more intriguing. The medium price of an AT is around 100$ and for the price of the GXW4108 you receive eight ATAs. If Grandstream fix the few bugs around their device it will become a block buster for sure.