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EMS-1 (The ITEC Electronic Modular Switch is an electronic direct control switching system. The modules are combined to form a complete switch or any of the modules can be added to your present Step-by-Step Systems.) EMS-2 (The EMS-2 RURAL SWITCH is a stored program control analog switch designed to be cost-effective in small exchanges.
The Strowger switch is the first commercially successful electromechanical stepping switch telephone exchange system. It was developed by the Strowger Automatic Telephone Exchange Company founded in 1891 by Almon Brown Strowger. Because of its operational characteristics, it is also known as a step-by-step (SXS) switch.
In data communications, an automatic switching system is a switching system in which all the operations required to execute the three phases of Information transfer transactions are automatically executed in response to signals from a user end-instrument. [1]
The GTD-5 EAX (General Telephone Digital Number 5 Electronic Automatic Exchange) is the Class 5 telephone switch developed by GTE Automatic Electric Laboratories. This digital central office telephone circuit switching system is used in the former GTE service areas and by many smaller telecommunications service providers .
The Panel Machine Switching System is a type of automatic telephone exchange for urban service that was used in the Bell System in the United States for seven decades. The first semi-mechanical types of this design were installed in 1915 in Newark, New Jersey , and the last were retired in the same city in 1983.
The Lucent 5ESS, a class-5 switching system, is sometimes used as a class-4 switch (or as a mixed class-4/5 switch) in markets that are too small to justify a 4ESS switch. The Nortel DMS-250 , a larger variant of the DMS-100 , is a popular competitor to Lucent's 4ESS, especially among telephone companies that were not previously a part of AT&T.
With the advances of digital electronics starting in the 1960s telephone switches employed semiconductor device components in increasing measure. In the late 20th century most telephone exchanges without TDM processing were eliminated and the term electronic switching system became largely a historical distinction for the older SPC systems.
In contrast, direct control systems have subsystems for call control that are an integral part of the switching network. Strowger exchanges are usually direct control systems, whereas crossbar, and electronic exchanges (including all stored program control systems) are common control systems. Common control is also known as indirect control or ...