The Evolution of a Phone - Research Paper Example

?Soohaeng Lee Clay L. Housholder 367 4 March The evolution of phone Communication is a vital aspect of animal life. Human beings mostly use sound to communicate with one another. While the drums, bullroarers and resonating rock gongs (Waller13; Fagg 27) played an important role in long range communication in primitive cultures, the present-day communication devices are based on telephony. For effective communication over long distances the telephone has become invaluable. The Public Switched Telephone Network (PSTN) started in 1880 is the largest communications network in the world today. The word telephone comprising of a combination of two Greek words, tele (far off) and phone (sound) was the name given to the electric device invented and patented by Alexander Graham Bell in 1876. The first operating telephone sets were restricted by the wire that connected pairs of telephones. Since then, the evolution of the telephone has passed through a range of important yet exciting stages, including the introduction of the automatic branch exchange with a series of switches instead of the human operator, the emergence of dial exchanges, and the induction of wireless communication that paved the way for worldwide communication. Alongside these developments, arrays of features of the handsets also underwent a sea change to yield the latest generation of smartphones. Interestingly, however, the basic technology has remained mostly unchanged for more than a hundred years (Dennis 1). The most rapid expansion of the telephone industry occurred during the late 19th century and early 20th century. Following a brief explanation of the basic principles of the telecommunication systems, this essay discusses the amazing progression of the device from the initial cranking set to the smartphone, describing the associated developments in the size, shape, material and features of the device. The changes that have occurred in the telecommunication infrastructure such as the computerization of the switching system, digital transmission using fiber optic cables, transmission towers for cell phone networks, and telecommunication satellites have also been dealt with. Finally, how the telephone affects our day to day lives by impacting the economy and the society is elaborated upon. Basic information The basic requirements of a telecommunication system include, at the place of origin, a speaker, a transducer that converts the original information energy into electrical energy to produce the information signal, an amplifier to increase the power of the signal to compensate for losses occurring during transmission, a wire or cable link to transmit to its destination the signal travelling at 60% the speed of light (“Telecommunication”). Besides the above, at the destination point another transducer converts the received signal back to its original energy form, while a second amplifier increases the power of the signal. Telecommunication System Components The components of a complete telecommunication system comprise of (1) the source of the message, for example, a voice signal which as stated earlier is converted by a transducer to electrical signals; (2) a transmitter that modulates the signal suitably for transmission. The reason is that the original audio frequency created in a low frequency waveform is unsuitable for transmission and needs to be translated to a higher frequency that can be transmitted; (3) a channel or a carrier system, which is nothing but the transmission path that transfers the modulated signal to the receiver via a medium. The different channels that are made use of are wires or cables, radio waves and light waves; (4) a receiver that receives the incoming signal after selection of the appropriate signal from a gamut of signals passing through the channel. The receiver also demodulates the signal to reproduce the original information; and (5) a destination device that further processes the signal that is, receives, stores or re-transmits the signal (“Tele-communication”). Channels and bandwidth Global long range telephone systems generally employ 12-channel groups. The 12 voice channels of modulated frequency occupy a 48 kHz bandwidth lying between 60 and 108 kHz. Further, a supergroup made up of 60 channels from combinations of five 12-channel groups, or a 300-channel mastergroup formed from 5 supergroups, or a supermaster group formed by 3 mastergroups and comprising of a 3872 kHz bandwith are the larger assembly stages that can be formed (International Telecommunication Union 1). The International Direct Dialing (IDD) codes for different countries are given by ITU-T. The earliest telephones were connected to the exchange through the local loop which soon led to the formation of networks formed by linking exchanges via trunk lines. The trunk lines initially consisted of UTP cables which, in the 1930’s, came to be replaced by coaxial or microwaves used with Frequency Division Multiplexing (FDM) which could maximize efficiency of the long distance trunks through combining multiple analog voice signals in single lines. In the 1960’s, FDM was substituted by Time Division Multiplexing or TDM which was capable of transmitting multiple signals simultaneously over a single transmission path which also enabled the exchange to changeover from analog circuit to digital circuit (“TDM” 1). Thus, the basic structure of the exchange network is tree-like: the subscribers at the bottom are connected to the primary exchange in the local loop, while the main trunk links the primary exchange to the secondary exchange which, in turn, connects to the tertiary exchange. Extra trunks or auxiliary trunks are provided to build in redundancy in order to serve busy routes directly (“Imperial College”5). The step-by-step or automatic telephone exchange was followed by the Reed Relay and Crossbar Exchanges incorporating electromagnetic devices to control the operation of a switching matrix (Smith 4). Transmission Media The physical path traversed by the modulated communication signal between the transmitter and receiver is known as the transmission medium. The length of the transmission medium could be extended by the use of repeaters or amplifiers (“WPI” 2). The transmission media employed in networks have ranged from the early copper wires to satellite channels. The communication of the electromagnetic waves is achieved through either guided or unguided media. In the former, metallic cable (twisted pair and coaxial, made of copper or steel coated with copper) and optical fibers are utilized to guide the electromagnetic waves. On the other hand, the unguided media are wireless communications such as radio signals and satellite signals which are only means of transmission of waves but do not guide them. Each of these different media has characteristic bandwidth, that is, each transmits within a specified range of frequencies. Generally media with greater bandwidth can carry more signals (“Telecommunication”). Twisted pair cables are limited in distance, bandwidth and data rate on account of attenuation problems, interference ‘cross talk’ from other signals and noise. Coaxial cable, consisting of a conductor in the centre of a dielectric material surrounded by a braided outer conductor within an outer cover, provides much higher bandwidth than twisted pair but the cable is bulky. The optical fiber, on the other hand, is a thin and flexible medium. It is made up of a core of very fine glass cylinder embedded or cladded in concentric layers of glass. The medium is capable of conducting optical rays by total internal reflection within the core that occurs because the core has a higher optical density than the cladding. Attenuation is reduced by controlling the impurities in the glass. Higher speeds can be achieved by using a narrow core that creates a single direct path. With optical fiber, detectors that convert light into electrical energy that is, photo diodes are needed at the receiving end. For the transmission of digital data over optical fiber, Amplitude-shift keying (ASK) modulation is used. The Telephone Instrument The telephone essentially consists of a microphone within which the conversion of the audio signal to electrical signal happens. The speech into the microphone causes high and low pressure within the microphone resulting in the generation of electric signals that are eventually conveyed to the exchange via the subscriber trunk line. The receiver re-converts the electrical signal to sound. Two amplifiers in the speech circuit aid in the amplification of the microphone current and feeding of the receiver. Besides the components of the speech circuit described above, the telephone instrument also consists of (a) a bell, (b) a cradle that acts as a switch that connects the instrument to the exchange when the handset is placed on the hook and, when off hook, the bell gets disconnected but the keypad and speech circuit become linked, and (c) a keypad or dial depending on the type of telephone. A variant of the telephone instrument described above is a pay phone that registers the amount of money inserted and controls the charging with the aid of pulses conveyed to the exchange. The telephone answering machine is a device having a built-in tape recorder for leaving messages and its own cradle switch function which gets activated after a specified number of ringing signals. The early telephones were anything but user friendly. Getting connected to the operator by turning a crank handle was not easy but the introduction of the rotary dial solved this problem to some extent. Telephone designs became more standardized with the advent of new materials such as Bakelite. Modern plastics and injection molding techniques have led to the production of sleek, colorful, ergonomic and lightweight instruments. Mobility while talking became an attractive proposition to many, leading to the appearance of cordless telephones in 1980. The wireless handset in this type of telephone links via radio waves to a base station within the home that is connected to a fixed telephone line. In other words, a cordless telephone is a combination of a telephone and a radio transmitter/receiver (Freudenrich 2). Facsimile or Fax A further advancement of the basic telephone and communication technology has enabled digital signals to be transmitted by a Fax machine over telephone lines to a modem on the receiver which decodes the signals into messages or pictures. Fax machines first convert an image into a grid of dots that is, digitize the image. The dots are either on or off which depends on whether they are black or white. Next, the fax machine converts the picture into a bit map that is, a series of zeroes and ones, a zero being off and one being on. At the receiver end, the bit map is re-translated into dots and re-prints the picture. A fax machine, thus, essentially consists of an optical scanner for the digitization of pictures on paper, a telephone for making the connection, and a printer to download incoming fax messages. Mobile or Cell phone Cell phones appeared in the early 1980s and changed, forever, the way people around the world live. Started as paging systems that alerted a user carrying a pocket receiver that (s)he was wanted, mobile telephony based on wireless communication was a great leap ahead in the telephone history as it allowed using one apparatus and one number within a city and country, and, now, from and to anywhere in the world (Novitskaya 1). The cellular mobile telephone technology relies upon a series of 'cells', each with its own central radio transmitter and receiver. As for the bulk, it makes sense if a stationary telephone is of any reasonable size. However, a mobile phone has to be compact and light weight for convenience of carrying around. Following the development of miniature microcircuits the receiver size diminished to one that could easily fit into a palm. Freeing the cell phone of a hand-held receiver occurred next with just an ear-piece attached to the head, and a microphone being used. When a wanted telephone number is keyed into a mobile phone to initiate a call, the information is conveyed over the control channel to the base station. The mobile telephone switching office (MTSO), that automatically controls and maintains all calls inititiated or received by a mobile in its cell, allocates a speech channel that is free to the mobile and sets up the required connection via the PSTN. The end of call is signaled by the mobile set to the base station by sending an 8 kHz tone of 1.8 seconds duration (“Telecommunication”). However, in times of natural disasters such as typhoons the base stations and towers could get badly damaged. A new study by Swedish scientists describes how the new generation mobile phone technology could enable direct communication between telephones without the necessity for base stations (Asplund et al.,1). The telephone – Social and environmental impacts From around 11 million subscribers in 1990, the number of cellular subscribers world-wide was predicted to exceed 550 million by the end of 2008 by the ITU (Epand 1). Mobile telephony offers enormous advantages by way of utilizing dead time through business promotion while on the move, being accessible to family and friends at all times, and generally ensuring greater personal security. However, it also has a down side. Besides some real concerns about its impact on the environment and societal health, being constantly contactable can affect interpersonal interactions, leading to psychological problems. The diminishing of distances by the telephone can lead to a decrease in direct social contacts. The innumerable mobile antennae that dot the cities spoil the aesthetics. Besides they also detract from the natural beauty especially of historical areas. Smartphones of the future According to Juergen Stark, VP and GM of Motorola’s Mobile Devices, "There are three key trends that will cause a fundamental change in the role and nature of smartphones over the next few years: broadband everywhere, digitization of all content, and pocket computing power" (Zeman 3). The future evolution of the smartphones will ensure that they have faster access to mobile networks, are always internet connected, have very powerful and speedier processors, have much greater memory capacity, and would be capable of providing a much wider array of personal services including signing contracts on the telephone, telephone banking, or even for recording conversations in hospital operating rooms using the Voice over IP, or VoIP principle. There is a strong possibility that one will be able to experience mobile Internet in three dimensions in the neat future. Scientists at the Fraunhofer Institute for Telecommunications, Heinrich-Hertz-Institut, HHI in Berlin, Germany have used the Multiview Video Coding (MVC) technique to reduce the size of 3-D films by about 40 per cent which ensures quick retrieval of 3-D films of excellent quality in connection with the new 3G-LTE mobile radio standard. It is the radio resource management integrated into the LTE system that is actually responsible for allowing flexible data transmission (eScience News 1). The mobile phones of the future could be powered by power-generating rubber films capable of harnessing natural body movements such as breathing and walking to generate power by converting mechanical energy to electrical energy (“Princeton University” 1). In conclusion, the evolution of telephone during the last one hundred years has traversed a rapid and exciting path. The rate at which technology is developing promises the advent of new generations of smartphones having immense capabilities to change the world in unimaginable ways in the years to come. Works Cited Asplund, Mikael et al. Mobile telephony without base stations. Expertanswer (Expertsvar in Swedish) ScienceDaily, 13 Jan 2011. Web. 22 Feb 2011. Smith, Ed. Preserving the Telecommunications Industry Heritage – the Holy Island UAX13 Exchange. The Journal of the The Institute of Telecommunications Professionals, 2010. Web. 21 Feb. 2011. Dennis, Tony. Evolution of the telephone explained. 27 Nov. 2008. Web.18 Feb. 2011 Epand, Victor. 2007. Social impacts the telephone and the cell phone has had on society. n.d. Web. 21 Feb. 2011. eScience News. MWC 2011: 3-D films on your cell phone. 11 Feb. 2011. Web. 22 Feb. 2011. Fagg, Bernard. The rock gong complex today and in prehistoric times. Journal of the Historical Society of Nigeria, 1 (1956):27-42. Print. Freudenrich, Craig. How cordless telephones work. n.d. Web. 20 Feb 2011. International Telecommunication Union Telecommunication Standardization Sector, ITU-T). Recommendation G.341. 1993. Web. 18 Feb. 2011. Novitskaya, Elena. Evolution of the shape of telephone components. Generator, 15 Mar. 2004. Web. 20 Feb. 2011. Princeton University Engineering School. Energy-harvesting rubber chips could power pacemakers, cell phones. ScienceDaily, 28 Jan. 2010. Web. 22 Feb. 2011. TDM, The Free Dictionary. Web19 Feb. 2011. Waller, Steven J. Rock Art Acoustics in the Past, Present, and Future. 1999 International Rock Art Congress Proceedings, 2 (2002):11-20. Imperial College Department of Computing. The Telephone Network. Lecture Notes. n.d. Web.19 Feb.2011. < http://www.doc.ic.ac.uk/~pjm/nac/lecture_telephone.pdf> Telecommunication. Web. 19 Feb. 2011. WPI Worcester Polytechnic Institute Computer Science Department. Transmission media. n.d.Web.19 Feb. 2011. < http://web.cs.wpi.edu/~rek/Undergrad_Nets/B04/PL_Media.pdf> Zeman, Eric. Smartphone 2010: What your future phone will be packing. Information Week 23 Feb. 2008. Web. 22 Feb. 2011. Read More