I'm trying to understand what a PBX or Asterisk server is. I don't understand the explanations I've found on websites via Google or wikipedia because they use too many technology words I'm unfamiliar with (eg. voip gateways, IP-PBX, conference servers etc...)
Basically, I told a friend that I have a small business with 10 freelance programmers. It would be great if my business had one phone number like 111-222-3333, and each freelancer can have an extension that routes to their cell phone. That way, freelancers never have to expose their personal phone number to the clients. My friend told me to look into setting up an Asterisks server. But in my research, I can't tell if Asterisks will do what I need.
Can someone explain to me, as if I were 12 years old, what an Asterisk is and whether it will do what I need? Are there other "cool" things an Asterisk server can do for my business?