Voice Over IP

THE INTEGRATED SERVICES DIGITAL NETWORK (ISDN)

In the 1960s and 1970s, as digital technology began to find its way into the telephone providers' networks, and as the costs of digital technology declined, the telephone industry began to look for ways to move this technology into the local loop. The telephone service providers' view was that the superior characteristics of digital technology (over analog) would make it attractive to the customer.

Additionally, the use of analog signaling over the local loop was quite limited with regard to data rates (in bit/s). In fact, when ISDN was first introduced in 1984, the V.22 bis modem was just introduced, operating at only 2400 bit/s! So, a 64 kbit/s rate sounded very attractive to the data user.

Then ...