We have a small bussiness, I need a phone system that can talk just internally at the company , we only use phone phone number for people to call , it is a bar/nightclub with multiple floor and I just want my staff to be able to call each floor . What’s the best way to go about this ?
Most of the phones allow direct IP calls. Many of the phones allow assigning IP addresses to speed dial buttons allowing dialing with a single push - just make sure phones have static IP addresses and add labels to speed dial. You can also setup multicast RTP streaming for a one-way broadcast from a phone to all other phones or some group.
For a few more features (and some reliability loss) you can either buy some cheap new/used small PABX or register phones to some online service (there are free ones if you would be calling only “inside” this provider, though there might be privacy concerns).