Summary: Once set up (which was a pain in the ass), it works completely flawlessly with asterisk. I have one that currently is reporting that it is in it's 482 day of system up time. We've had no echo problems.
Summary: The Grandstream 4FXO seems to be a good gateway for the price; however set it up and get it to work with the minimum documentation is a real challenge not everybody is willing to take. To setup the box, it needs to be plugged to a LAN with DHCP and then find out what IP received. You must download an application (that requires a couple of additional pieces of software ) and wait for a long while until it detects the box which is far from simple.
Summary: just followed the instructions on line and have it running with 4 time warner digital lines. only issue is that i can't get it to work with 4 trunks and have to use all 4 DID on one trunk. only 1 trunk would ring. i found a line to add on the truck settings but haven't tried it since it works well for what we need as a single trunk.
Summary: I was able to to configure the unit to work with my POTS line as well as 2 magic jack lines. The web interface is similar to other Grandstream adapters (e.g. HT503). I haven't had to reboot the unit due to hang ups or other malfunctions and the price is good compare to other similar products. All in all, I would highly recommend.
Summary: This is an easy to use device, which with IP infrastructure allows you the use of the PSTN (public telephony) in different remote locations as if they were at the same location.------ ++ Easy to set up and use.----- + Good manufacturer's technical support.----- I recommend this product for small bussines where can save you time and money with phone comunications.----- This little black box saved me life and work !!!!