“Extension” - is the extension of the telephone line (PBX) or the Centrex system. It works as an association and allows calling to certain telephone sets without the necessity of dialing the telephone number, but only by dialing a short combination of digits, reaching the desired subscriber.
Companytel is a italian company created in Rome , specialized in the development and production of telecommunications equipment. It is comprised of specialists in the design and production of data and voice transmission equipment.