3com NBX with Asterisk

We currently have a PRI going to a 3com V3000 NBX system. We would like to take several DID’s from that PRI and reroute them to an Asterisk box. Not sure how to begin doing this.
NBX system is running version 5_0_28. Not sure if this version is running SIP or h223 or something else.

I was trying to do the same for a customer and i talked with a 3com Technician and he told me that You just have to upgrade to version 6_5_22 , and if you enable the SIP MODE on your 3COM PBX all the information will be erase so my suggestion is connect Asterisk and 3COM trough a T1 Trunk. Check you have slot available in your 3COM and if not you need to purchase chassis and the T1 card for the 3COM PBX