The information driveway [using analog telephone lines]

Regular analog telephone lines can be directly connected through the telephone network to ISDN terminals. By using appropriate modulation formats, they can carry digital traffic at rates approaching those of ISDN, without extra recurring costs for the customers or new investments in the network. Such a system thus provides an affordable and universal "driveway" to information services. This article explains the basic concepts and reports on some measurements that show their feasibility.