What does “lines” mean on FlexPBX?

I am looking at the Flex PBX an want to know what you mean by lines. Is 1 line mean a one to one connection as in I call the front desk from my office an now HR can\’t call admin because the line is in use. Or is it one outside line into the system as in a VoIP line. or PSTN trunk with 24 connections?

1 line would be the call to your number, then once the phone is connected any other phone calls within your office would be an internal line. The internal lines are not consuming outside lines as long as all of your employees use our soft phone software. You only need to purchase enough lines to handle all of your incoming calls.