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Of the many wonderful scientific discoveries and inventions which have made the nineteenth century remarkable, certainly none is of more popular interest than the simple little piece of apparatus known as Bells articulating telephone. By this instrument it becomes possible to transmit ideas between far-distant places, not in the form of signs afterwards to be deciphered, but as actual articulations, an echo of those produced by the human voice at the point of transmission.
Wonders of the Universe, 1899
The old networks were designed around voice traffic, or Plain Old Telephone Service (POTS). Telegraphy was conducted over a separate, pre-existing network. As data, image, and video systems didnt exist until many years later, there certainly was no requirement to network them. The characteristics of voice traffic were, and still are, well known and easily understood. Specifically, voice calls are occasional, short, bidirectional, continuous, and analog in their native form.
Voice calls typically are only occasional, as most humans have things other than talking on the telephone to occupy their personal and professional lives. Clearly there are exceptions, such as agents who work in call center environments as we examined in Chapter 4 during the discussion of ACDs. Human-to-human voice calls also tend to be shortthree minutes or so, on average. Clearly, business calls tend to be short and to the point, while purely personal calls tend to be longer and more social. Additionally, some people (e.g., the author) tend to express themselves in very concise terms, while others (e.g., the authors mother) tend to be very wordy. (The author begs the reader to hold this comment in confidence.) Voice processing, of course, tends to abbreviate voice communications as we noted in Chapter 5.
Clearly voice calls are conversational, or bidirectional, in nature. Further usage of the circuit is fairly constant, or potentially so. Regardless of the direction of the conversation (talking vs. listening) and the number and length of pauses in the conversation, the network is required to support the communication when it is active. In other words, voice is isochronous, or stream-oriented; the network must be available to accept, transport and deliver the communication when it is active. Finally, the native information is analog, rather than digital.
Analog transmission over copper twisted pair was quite suitable, and for many years this remained the case. Circuit switching also was quite suitable and still is, although it is giving way to other techniques (packet, frame, and cell switching). Manual switchboards eventually gave way to SxS, XBar, and ultimately, ECC switches. Switches were interconnected with other switches for longer distance connections, and so on. Contemporary networks, of course, are much more sophisticated, supporting huge volumes of voice, as well as data and even some level of video and image transmission. Analog has given way to digital, copper has yielded to fiber, and wires have given way to wireless communications in many applications.
As more people became comfortable with the telephone, more people subscribed to telephone service, which made the technology more useful. Businesses came to depend on telephony, and usage increased further. Costs began to drop, so that the technology became affordable, and usage increased even further. Long distance usage, which is highly profitable, began to increase, especially as rates were reduced.
Independent, privately-owned telephone companies sprang up all over the world, with thousands of them appearing in the United States; approximately 1,500 U.S. independents (non-Bell companies) still exist [6-1]. Around the turn of the 20th century, the Bell System had approximately 800,000 telephones in service, compared to about 600,000 for the independents [6-2]. In many cities and towns, there were multiple telephone companies operating in direct competition under franchises granted by the local government. In rural areas which were not commercially viable telephone cooperatives and municipally-owned telephone companies were formed, a number of which still exist.
Initially, these networks were isolated islands of local service; in other words, they were not interconnected. The telephone companies soon interconnected with each other and with the long distance network, usually under government/regulatory pressure. In the United States, the Bell System avoided providing interconnection, preferring to aggressively acquire the independent telephone companies and even acquiring a large block of stock in Western Union, its chief competitor. Under increasing pressure by the federal government under antitrust laws, Nathan C. Kingsbury, an AT&T vice-president, in December 1913 wrote a letter to the U.S. Attorney General to resolve various issues. Known as the Kingsbury Commitment, that letter committed AT&T to dispose of its holdings in Western Union, to purchase no more independent telephone companies without the approval of the Interstate Commerce Commission (ICC), and to make interconnection with the independent telephone companies. Eventually, standards were established to govern the nature and rules of interconnection. These standards are the responsibility of the ITU-T at the international level.
Many nations acquired or even confiscated the telephone networks from the private owners, forming Post, Telegraph and Telephone (PTT) agencies. The British government on January 12, 1912 assumed full control and ownership of the national telephone system, leaving the United States as the only major nation in which the network was privately owned. Eventually, access to telephone service was viewed as a basic human right in many industrialized nations. As a result, the concept of universal service was born; formed by an act of Congress in 1935, the Federal Communications Commission was chartered with accomplishing this goal. The motto (admittedly paraphrased) of the Bell System, for instance, became universal service of the highest possible quality at the lowest possible cost.
Governments have discovered that they cannot easily fund the capital-intensive upgrades their networks require and that they cannot effectively serve the communications needs of their constituents at reasonable cost. They also have come to recognize that the networks are immensely valuable assets that can be sold to fund various social programs. Therefore, the networks have been opened to competition in many nations. The networks also rapidly are being privatized, either completely or partially, with the government typically continuing to hold controlling interest for some period of time. As a result, service has become more universally available, the quality of service has improved, the range of services has increased and the overall cost to the user has dropped considerably.
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