soulofdoom

if you have a server/computer laying around vmware esxi does pretty well..and its free

I've deployed Siemens Optipoint headsets..their a pain to configure and have issues detecting dhcp..most of the time you need a wifi system that can handoff to another access point as well as broadcast the same SID..yea its quite the investment and can turn into a nightmare..but if you need weve used aruba acess points along with the aruba acess point manager works pretty well just dont expect perfection.

You can separate the extensions/sip account by context and put it in the same context as your dialplan..so that is only accessible by that extension