The Telephone Exchange (1982) British Telecom Schools Film

Summary

This script delves into the history and evolution of telephone exchanges, from the manual operator days to the advent of electronic and automated systems. It highlights the pivotal role of Almond B. Strowger, who invented the first practical automatic exchange, and discusses the progression to crossbar and electronic exchanges. The narrative also explores the future of telecommunication with the introduction of silicon chip technology, promising faster and more efficient call connections, alongside innovative services like contravision and the potential for a more personalized and advanced telephone system.

Takeaways

• 📞 The telephone has been a part of daily life for over a century, evolving rapidly with the invention of telephone exchanges to manage the growing number of connections.
• 🔄 The necessity for telephone exchanges arose as soon as more than two telephones were in use, to connect calls between them, leading to the development of various types of exchanges.
• 🏔 The first practical automatic telephone exchange was invented by Almon B. Strowger, an undertaker from Kansas City, who was motivated by the need to prevent competitors from diverting his calls.
• 🔩 Strowger's invention introduced the concept of an automatic selector that could connect calls without the need for an operator, laying the foundation for modern telephony.
• 🔄 The evolution of telephone exchanges continued with the advent of crossbar switching, which improved reliability and speed over previous electromechanical systems.
• 🛠 The crossbar system used a matrix of contacts and electromagnets to automatically connect calls, refining the basic principle of plugging in a socket used by early operators.
• 📡 The introduction of electronic exchanges in the 1960s marked a significant leap in efficiency and capabilities, with the first electronic switching invented back in 1919 but only becoming practical with advancements in solid-state components.
• 🔌 The development of the reed relay switch in 1936 was a significant step towards more reliable electronic switching, using two metal reeds that move together in a magnetic field to make contact.
• 💡 Modern electronic exchanges are capable of high-speed traffic handling and even self-diagnosing faults, pointing engineers to areas that require investigation.
• 🌐 The future of telephone exchanges is being shaped by miniaturized circuits and silicon chips, which can contain thousands of switches and enable new services and capabilities.
• 🚀 The new generation of exchanges, known as System X, will route calls at nearly the speed of light and offer unprecedented facilities, revolutionizing the use and service of telephones.

Q & A

What is the significance of the telephone in our daily lives?

The telephone is a crucial part of our daily lives, often taken for granted, but essential for communication. It has evolved rapidly over the years and has become indispensable for both personal and professional interactions.

How does a telephone call get connected to the intended recipient?

A telephone call is connected through a series of switches and signals that are transmitted through wires or digital pathways. When a number is dialed, the telephone exchange routes the call to the appropriate line, facilitated by various technologies like Strowger's automatic switch, crossbar, and electronic exchanges.

Who was Almond B. Strowger and what did he invent?

Almond B. Strowger was an undertaker from Kansas City who invented the first practical automatic telephone exchange. His invention was motivated by the need to prevent his competitors from diverting calls meant for him, and his system laid the foundation for modern automatic telephony.

What is a crossbar exchange and how does it work?

A crossbar exchange is an electromechanical switching system that uses small electromagnets to energize horizontal and vertical bars. These bars operate in sequence to connect the call to the desired number, providing a more reliable and faster alternative to previous switching methods.

What is the role of a common control unit in a telephone exchange?

The common control unit in a telephone exchange acts like a computer, determining the best route for a call and selecting it. It guides the call through various switching stages and can even pass the call onto other exchanges if necessary, ensuring efficient and rapid connection.

How have electronic exchanges improved the efficiency of telephone systems?

Electronic exchanges have greatly improved the efficiency of telephone systems by offering faster switching, smaller and more reliable components, and the ability to handle a larger volume of calls. They also allow for self-diagnosis of faults, enhancing maintenance and reliability.

What is a Reed relay and how does it function in telephone exchanges?

A Reed relay is a type of switch that uses two metal reeds moving together in a magnetic field when energized, making contact. It is known for its reliability and was used to replace mechanical switching in telephone exchanges, especially for handling the large number of contacts required for calls.

What advancements in electronics have led to the development of System X exchanges?

The development of miniaturized circuits and silicon chips has led to the creation of System X exchanges. These tiny integrated circuits and chips allow for faster call routing at nearly the speed of light and provide a range of new services and facilities.

How have telephone exchanges evolved over time?

Telephone exchanges have evolved from manual operators to Strowger's automatic switch, then to crossbar and electronic exchanges, and now to System X exchanges using silicon chips. Each advancement has increased speed, efficiency, and the range of services available.

What is contravision and how does it relate to telephone exchanges?

Contravision is a form of closed-circuit TV developed by British Telecom that uses cables and microwave links to carry picture and sound, enabling people in different cities to communicate visually and audibly. It represents one of the many ways in which telephone exchanges and networks have expanded to include multimedia communication.

What is the future of telephone exchanges and what role will they play in communication?

The future of telephone exchanges is likely to involve further advancements in technology, such as even smaller and faster switches, integration of multimedia services, and potentially new forms of communication yet to be developed. They will continue to serve as the backbone of global communication networks, adapting to the needs of users.