In essence, VOIP is phoning over the LAN (internally) and Internet (externally) in stead of over a dedicated phone network. Of course, it needs software to run and be managed.
You can either use it as a service offered by a VOIP provider or install the necessary software on your own server.
The user side has even more variants:
- you can buy fully equipped VOIP phones that look and work just like standard phones but plug in into your local network on its own (like a network printer or network storage)
- you can use a headphone and software (to dial and forward and choose a number from the phonebook or dial the current customer whose phonenumber is on the screen) on each PC; skype is a basic consumer oriented example of such an application
You can even mix: use VOIP software and hardware internally, and connect it to your current PABX to handle incoming and outgoing calls via the POTS (plain old telephone system). Or the other way around: use your traditional phones, but replace your PABX by a VOIP one.
Obviously, the optimal use of such technology (of all technology in fact) depends on the circumstances. The best thing to do is to contact a few local companies and let their sales person make an offer for hardware, sofware and services that optimally suit your need.
I'm expecting a view spam answers advocating a particular company as the best for you, but clearly that can't be said without researching your specific situation.
Best of luck mith your business.
My maximum business runs on telephone. I have heard about Voip, so want to know more about it. There are around 25 employees in my company is it worth taking any Voip business solutions? What are the different solutions?