Overview

ATM began development in 1969, when engineers at Bell Laboratories began experimenting with alternative switching techniques for routing data of all types through a common switching point. This would alleviate the need for multiple types of equipment in the central office and would provide a much faster, more efficient method by which data could be transmitted.

In the current telephone network, facilities are run from the central office to the subscriber over analog or digital lines. In most metropolitan areas, digital transmission is used up to the subscriber. This requires a multiplexer in the central office, as well as repeaters in the field. DS1s and DS3s are not used for facilities to the residential subscriber, so a different method of multiplexing is required.

These multiplexers (such as D4 and SLIC96) can be found in the field, close to the subscriber. However, using this method of distribution has proven costly to telephone companies due to maintenance and upgrades to support newer technologies. One example of this cost is ISDN, which cannot be used in many areas because the multiplexers used outside the central office will not support it. These must be replaced with compatible multiplexers before ISDN services can be offered. This has resulted in delays in providing ISDN in many rural areas.

ATM can provide a more efficient and cost-effective approach to distribution. By using one common facility throughout the network, telephone companies can rid themselves of the various pieces of equipment they own and maintain today. Using nothing...