we are using call manager express 3.3 on a 3660 router and about 80 employees are using VOIP but most of company use traditional analogue PBX. we want to use VOIP for all employees (about 700 employee). we have 3 building that are connected together with wirelesee RF as a transparent LAN (wireless bandwidth is about 18mbps). first choise is using single site model we want to use communication manager business 6000 and use old router as gateway. is it good solution or not and how many license and what type should we purchase?
second choise is to us call manager express in 2 branch building and use communication manager business 600 in head quarter? should we change LAN design or not and what is your suggesstion for devices?