Yeah, the differences between the 2100 and the 9100 is scarce, past the 9100 having more expandability, and the 9100 having the CAP keys (which are useful for large organizations, or any anybody with a PRI). Me and my coworkers keep a document of all the differences we've noticed, and it has 8 things in it, most of which don't matter (9100 has dhcp mode off by default, 2100 on by default)