Rather than fill the post with a ton of information, here's a link to another site where it's listed.
If you need more than one or two PRI channels and are getting into VoIP/SIP in a serious way, this is the machine to count on. It has EIGHT T1/PRI ports along with BOTH VoIP AND Dial-Up for the same price! SIP, VoIP, Dial-up, 48 digital (Analog/56K/ISDN) modems, 96 DSP channels, the list just goes on.
Since it is carrier class hardware, it's got all of the bells and whistles such as echo canceling, etc. It has a long list of features and is easy to look up on the net if you need more information. In fact, a few people have posted their configurations. It was surprisingly easy to set up but since we've not used it in some time, have no idea how to work with it anymore. It's already set up for SIP however.
Here's the link;