O'Reilly logo

CISSP All-in-One Exam Guide, Eighth Edition, 8th Edition by Fernando Maymi, Shon Harris

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

Telecommunications Evolution

Telephone systems have been around for about 100 years, and they started as copper-based analog systems. Central switching offices connected individual telephones manually (via human operators) at first, and later by using electronic switching equipment. After two telephones were connected, they had an end-to-end connection (end-to-end circuit). Multiple phone calls were divided up and placed on the same wire, which is called multiplexing. Multiplexing is a method of combining multiple channels of data over a single transmission path. The transmission is so fast and efficient that the ends do not realize they are sharing a line with many other entities. They think they have the line all to themselves.

In the mid-1960s, ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required