2nd IP

i have stupid question because im new in pbx

I have 1 ip from my provider where i use my pbx and all of my phones are connected in my office.
If i want to connect to my pbx outside of my network (from home) do i need 1 more ip from my provider?

The answer to your question is No. Olease read the documentation . .

can u tell me what documentation? like i said im new in pbx

I would start with at the bottom of this page:-

http://wiki.freepbx.org/