I read that as, can I setup an EZ8 and have it monitored by a central station without buying more equipment?
I have an M1G, but from what I understand the EZ8 has everything you need to connect it to the phone, so you could use that kind of monitoring without additional purchases (you hook your phone line to it). The monitoring itself costs more though...
Now if you wanted online monitoring (via a central station) then it sounds like you would need the ethernet expansion.