TAILIEUCHUNG - Lecture 25: The Telephone System

The telephone system remains as the backbone of low-cost telecommunications services in North America. An understanding of the telephone system is necessary when considering its use for data communications. Telephone: invented in 1874 by Alexander Graham Bell and patented in 1876 Single wire: In the beginning, the market was for telephones only. It is the customer who used to wire them between telephones using single wires and the earth as the ground or the other conductor to complete the circuit. . | CSN200 Introduction to Telecommunications, Winter 2000 Lecture-25 Telephone System The Telephone System: (Ref: Ch-4, Page-113 of your Text book) The telephone system remains as the backbone of low-cost telecommunications services in North America. An understanding of the telephone system is necessary when considering its use for data communications. Telephone: invented in 1874 by Alexander Graham Bell and patented in 1876 Single wire: In the beginning, the market was for telephones only. It is the customer who used to wire them between telephones using single wires and the earth as the ground or the other conductor to complete the circuit. Bell foreseen the problem of jumbling wires all over the city and formed the Bell Telephone Company, which opens its first switching office in Connecticut in 1878. The original problem soon returned: to connect every switching office became unmanageable, so second level switching offices were invented. Eventually, the hierarchy grew to five levels. Copper: At one time, 80% 0f AT&T's capital was the Copper in the local loops, the largest Copper mine. Now a days a variety of transmission media are used for telecommunication. Local loops consist of twisted pairs, although in the early days of telephony, uninsulated wires spaced 25cm apart on telephone poles were common. Between switching offices, coaxial cables, microwaves, and especially fiber optics are widely used. Local loops still carry analog signals but all interexchange lines are carrying digital signal. In summary, the telephone system consists of three major components: 1. Local loops (twisted pair, analog signaling). 2. Trunks (fiber optics or microwaves, mostly digital). 3. Switching offices. We will next look at three different topics related to these three major telephone components: 4. How to send digital data over the local loops, quick answer is modem. 5. How to collect multiple calls together and send them together, the answer is multiplexing. 6. How to do .

• Thư viện thông tin
• The Telephone System
• viễn thông
• bài giảng viễn thông
• Telecommunications
• Local loops
• System Package
• Accessories
• Planning for Installation
• Choosing Location
• Telephone Line
• Mounting the Main Console
• Dialogue Systems
• SDSs
• Data Pre Analysis Multidimensional
• System Specification
• Design
• Evaluation
• ADVANCED THERMODYNAMICS ENGINEERING
• mobile
• honeycomb system
• CDMA technology
• telephone networks
• subscriber management
• Employee Relationship
• Ownership Mentality
• Accurate Thinking
• Management Decisions
• Marketing the Master
• Telephone Warning System
• Lecture Data Communication
• Bài giảng Truyền dữ liệu
• Data communication
• Time division multiplexing
• Inverse multiplexing
• Business data communications
• Data communications
• Cable TV networks
• Telephnone system
• Internet access via telephone