Public Data Networks: From Separate PDNs to the ISDN - Josef Puzman, Boris Kubin - Google Books

https://books.google.de/books?id=ZY7qBwAAQBAJ&pg=PA113#v=onepage

Public Data Networks provide a comprehensive survey of PDNs, covering all major countries. PDNs allow efficient and cost-effective telecommunication between a terminal and computer, or between computers, regardless of who owns the data terminal. The…