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.
Generally, SIP IP phones do not work without connection to SIP registration server, but for SPA series it may work.
There is an odd way to make it and I can't recommend this, but you may try filling address book of each phone with records like "John Smith" with a phone number like [email protected] or sip:[email protected]. SIP and H323 phones are capable of making direct calls, we even use this sometimes.
You should be aware that in that case you will not be able to call number 203, but you will be able to choose the corresponding item in the address book.
Another way is described here and its about modifying dialplan. If it will work without registering it would allow you to call numbers.
