A PBX (private branch exchange) is a telephone system within an enterprise that switches calls between enterprise users on local lines while allowing all users to share a certain number of external phone lines. The main purpose of a PBX is to save the cost of requiring a line for each user to the telephone company's central office. PBXs use digital technology (digital signals are converted to analog for outside calls on the local loop using plain old telephone service (POTS ). Private Branch Exchange by Performance Media a private telephone network used within a company or organization enhancing communication with ease. Services to over 300 area codes are provided for better communication.