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).
I would buy a cheap appliance like a Grandstream UCM … can get one for around $200. Get some cheap IP phones to register to it and you can do intercom calls at no cost. You can add your analog line or a SIP trunk to the system to allow all of those phones to answer the main line or make an outbound call (which you should probably have in that environment for emergency purposes).
Get a cheap PBX in a box with a couple of WiFi enabled phones, so it will be completely stand alone, and you won’t need to run ethernet.
Something like a Grandstream UCM6300A or a Sangoma PBXact 25 will do the job.