I have a task to set up VoIP inside a small network (~20 Cisco IP Phone 303). Only for calls inside the local network. I have no previous experience with VoIP and I want to do everything in the most simple and reliable way.
After some googling I still have a question - is there a way to set up all ~20 phones manually, so there will be no need for VoIP server (e.g. Asterisk)? If yes, I will be grateful for any guidance, links or other material.