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AN ANALYTICAL APPROACH TO THE STUDY OF TELECOMMUNICATIONS RESEARCH In a survey of telecommunications research, what shall we include within the scope of the term telecommunications? We must take care not to limit the field to hardware tech- nology, for communications is basically a human relationship. Similarly, we must recognize that communications can occur via many alternate forms - travel, books, magazines, and presentations before audiences. These are but a few examples of communications that might be overlooked by researchers searching for more sophisticated forms of communications. In fact, a literal definition of telecommunications can be had from examining the origins of the word. Tele, from the Greek, means "distant." Communicare, from the Latin, means "to impart." "To impart at a distance," then, is the generic meaning of telecommunications. While that could include such archaic forms as notches on a stick carried by an aboriginal tribal runner, we shall limit our generic field to the currently popular use of the word. Chart I on page 7 provides a back- ground panorama of what we are talking about when we speak of generic telecommunications. The reader with additional per- spectives and creative thinking may be able to add more examples to the chart; what is already recorded, however, should suffice to emphasize the breadth of the subject. The reader might question including the category of "information processing" under the subject of telecommunica- tions. We are trying to illustrate that "communication" does not generally take place without some form of information processing. In our routine interpersonal communications, this processing is entirely within the two human beings involved, too intimately related to the human biological factors in the basic information transfer process to merit separate analysis. There are over six information processes between the brain of the speaker and the brain of the listener. In oral communi- cations the brain initiates nerve pulses; the pulses control muscles to generate sound and to control oral resonances and lip noises to change the ideas to acoustic waves; the waves hit the outer ear drum which is connected by the impedance trans- former (anvil hammer and stirrup) to excite the inner ear drum to stimulate the nerve pulses which reach the brain for inter- pretation. But there are some communications which do require a specific processing step outside the human participants; it is these that we have tried to identify as part of the total communications world. Using Chart I as the broad picture background, let us examine a more practical structure for further study. Our
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8 broad interpretation of the word, "telecommunications," has allowed us to examine a cosmos of information transfer, while, as a practical matter, the world of telecommunications is more generally understood to imply "means to impart informa- tion at a distance through the transmission of electromagnetic wave symbols." Some explanation may be needed in a few of the terms: l. The word "technical" is used to denote specialized professional activity. Just as medicine has its sensor (eye and ear) doctors and transmission experts (neurologists), communications also has its specialized areas of expertise which we have labeled "TECHNICAL RESPONSE ACTIVITY AREAS." Each of these areas can be a candidate for specific research projects. 2. In "Human Factors" we are attempting to find a term to cover those biological and psychological traits of man that are vital to the communication process. How do we per- ceive? What aspect of interpersonal communications is most significant to achieving interpersonal understanding of the subjects being covered? Can man be educated and trained to make better use of available man-made systems? This category includes the concept of ensuring that the human interface to the communication system is optimized from both a hardware and a software standpoint. The hard- ware/human factors interface might include such items as adequate frequency response, level, fidelity, contrast, bright- ness and definition, as well as size and shape to fit the human hand, eye or ear sensors. The software/human factors interface might include time-study designed operator routines to structure telephone calls for a maximum transfer of informa- tion in a minimum time. 3. By "System Architecture," we are making reference to the fact that communication media used have a certain structure that determines to a large degree their utility in meeting new challenges. We feel that there are cases where a new structure might provide more effective means for the public to avail itself of the benefits of the new technology. Examples: the present means to handle intra-organization procedures such as internal mail, telex or a teleprinter system are thus far mere extensions of past ways of handling input/ output and filing. The basic tools to do a much more effective job in office or interoffice procedures, including the genera- tion, print-out, editing, filing, coding, message handling, etc., are on hand. The bottleneck is the need for the design of an entirely new "System Architecture" that will tend to be
standard. As another example, distribution of television and other information to the home might better be achieved for long run needs via cable, waveguide or fiber optics. Existing systems such as TV broadcast and the mail are vulner- able in any change. Hence a new approach, involving technical, economic, social and political inputs, is needed for progress. 4. In identifying the "Legal Factors," we are calling attention to the thought that, in progress toward meeting the cited communication needs, there are as yet unresolved legal questions needing study and reconciliation. Some of these legal questions are based upon needed legislative action; they may also thread back into basic socio-economic problems. We have provided in Chart II a view as to the relative importance of research activities vs. needs. It is an attempt to respond to the question posed against the "needs" categories as to which of the response areas seems to hold the key to significant progress towards meeting that need. The reader may wish to develop his own appraisal. In any event, the chart can provide a framework for classification of efforts in responsive research. Richard P. Gifford Jared S. Smith General Electric Company Lynchburg, Virginia
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11 INTERDISCIPLINARY RESEARCH AND DEVELOPMENT PROBLEMS IN TELECOMMUNICATIONS I. Introduction The National Science Foundation (NSF) is properly concerned about the status of telecommunication research in this country in order to establish if we are in danger of losing our technological lead to other nations. The intent is presumably to take whatever steps may be necessary to retain our tech- nological superiority in the foreseeable future. An important related question is, of course, how well and how rapidly we are applying the benefits of existing advanced telecommunication technology in the public and national interests. Are some of the foreign countries, in fact, taking better advantage of the existing technology than we are - in exploiting its social and economic benefits? II. Real Concern In the background is the real concern and uneasiness about our own industrial and commercial exploitation of this tech- nology both for domestic needs and in international trade. We find ourselves all of a sudden in the early 70's with a substantial excess of engineering manpower and also at the short end of the balance of international trade. We are importing more products and services in telecommunications than we are exporting - a rather embarrassing position for the most technologically advanced country in the world. And this is happening at a time when our own engineering talents and production capacities are nowhere near fully utilized. So let us examine the situation in order to see how improvements might be brought about from the standpoint of new research. What type of telecommunication research should get the highest priority from NSF it the public and national interests are to be served? III. General Evaluation The United States has done remarkably well in advancing the state of the art in telecommunications in the past decades. Our research and technology have been unexcelled. Industry has expanded tremendously. Meanwhile the telecommunications of other countries have also advanced, in most cases with our help.
12 We are still substantially ahead of them in pure technology, though not as far ahead comparatively as ten or twenty years ago. There is no tangible evidence that we shall lose our technological lead in the near, or for that matter, in the foreseeable future, if we maintain our present level of effort in the "hard" sciences. From the standpoint of exploitation of the technology in our public interest, however, there is a general consen- sus that we are not doing so well. Many important areas of sophisticated telecommunications applications, such as education, health services, transportation, public safety and the general economy have not benefitted nearly as much from this technology as many of us believe they should. The advance in applications has many pitfalls and impediments and hence progress is slow. Why is this? The reason, of course, is that in apply- ing telecommunication technology to human needs and national needs, much more than technology is involved. In addition to vast and difficult system architecture and engineering problems, they give rise to conflicts of interests in industry and government. The issues raised involve social, economic, political, legal, regulatory and related problems. These issues, not being sufficiently resolved, are inhibiting the growth of the industry and delaying advances in very important tele- communication applications, such as cable television, domestic satellite services, interconnecting data networks, public broadcasting, educational networks, etc. IV. Interdisciplinary Problems Thus the bottleneck is not technological exploratory research, traditionally of direct interest to scientists and engineers. Further advances in more technology may, in fact, embarrass us more because we do not effectively apply all the sophisticated telecommunication technology which is now available to us and probably will not apply it for a number of years to come. The bottleneck involves problems in economic, social, political, legal and institutional areas where there is plenty of room, and need, for exploratory research. Such research and analysis, when carried out competently and objectively, would provide the basis for policy determina- tions in the public and national interests. Since it would include the "soft" sciences, in addition to the "hard" science of telecommunication technology, it would be very much of an interdisciplinary effort. It is this area that should get the highest priority from the stand- point of the National Science Foundation.
13 V. Present Efforts It should not be construed that the issues and questions raised, and listed below, are receiving no attention at the present time. A reference to the current trade and profes- sional press, in fact, will show that there is a relatively great awareness of many of these problems, some of which, particularly in the broadcast field, recur year after year. There is substantial effort on the part of many organizations, both public and private, with varying degrees of competence and objectivity, to resolve these issues in their own particu- lar favor. But most of these efforts, to date at least, cannot be classified as objective research and analysis to form a basis for sound long term policy determination. The shortcomings of these efforts may be summarized as follows: a. too meagre, in view of the very substantial public interest involved b. lack sufficient depth of professional competence on the part of the organizational units involved c. not sufficiently free from industrial and political bias and pressures d. lack appropriate institutional foundation to insure competence, objectivity, and continuity of effort. The appropriate analysis and resolution of these issues should be a serious national concern. It is, therefore, appropriate that the NSF ponder seriously this problem with a view toward giving a higher priority to the needed basic interdisciplinary research. VI. Interdisciplinary Telecommunication Research Center(s) Since the requisite talents and capabilities are not readily available, where can they be reasonably mustered to do this research and become the focal point for this type of interdisciplinary telecommunication activity? The most likely place to find the necessary talents is in the larger university environment where the separate disciplines of economics, law, sociology and related areas exist, in addi- tion to a good technical and scientific base. Then the appropriate interdisciplinary teams might be brought together to address these issues and explore objectively all relevant possibilities. Their findings and the result of their research could then be published with a minimum of political or industrial bias or pressure.
14 The question of promoting and establishing such inter- disciplinary competency in one or several environments out- side of government and industry is one that the NSF and NAE might consider seriously, because of the long range implications. VII. Specific Issues and Problems What are the interdisciplinary issues and problems which require and deserve significant research and analysis effort which the NSF may appropriately sponsor? Following is a representative, but far from complete list. No priority is intended because of the listing sequence. There is considerable overlap between the various items, but that is the nature of most of the problems: l. Nature of demand for broadband communication dis- tribution system. Who needs it, who wants it, and how much are they willing to pay for it? 2. Impact of CATV on education a. elementary schools b. secondary schools c. universities and colleges d. adult education If favorable, how can it be enhanced and speeded up? 3. Telecommunication technology and impact on social services - health, education, welfare, public safety, etc. Is the rate of progress satisfactory? 4. Relative merits of private ownership and exploitation of broadband telecommunication systems, versus municipal or public ownership. 5. Public versus private ownership in the operation of other telecommunication facilities, such as common carrier, broadcast, etc. 6. Regulation in the public interest. What are the necessary ingredients for effective and timely regulation? Does the regulatory body have an adequate source of unbiased technical and other relevant information necessary to do an effective job?
15 7. Federal, State and local jurisdictions in tele- communications . 8. What rate of growth of the telecommunication industry is in the public interest? 9. Impact of TV on society. l0. Censorship in telecommunications, including broad- casting. 1l. TV programming - what alternatives are there? What are the merits of these alternatives? l2. Political use of telecommunications - Fairness Doctrine. l3. Advertising influence on TV programs. l4. Cost and pricing of telecommunication services. Marginal costs. Cost averaging. Effect on potential competition. l5. Savings and capital needs of the telecommunications industry. l6. Franchising of telecommunication services. l7. Copyright laws and their applications to TV, CATV and telecommunications in general. l8. Open channels - who pays for them? l9. Who pays for broadcast services? - What are the merits of alternatives to the present system? 20. Is competition in telecommunication necessarily in the public interest? Is there a good case for natural monopoly - with effective regulation? 2l. Should the rate of technological growth in tele- communications be encouraged, restrained, or left alone? Is the rate of obsolescence of telecommunications equipment too rapid from the public interest standpoint? 22. Should CATV be regulated? Why and by whom? 23. Spectrum utilization policy guidelines, taking into consideration technical, economic, social, legal and inter- national aspects. 24. International aspects of telecommunications. Dealing with foreign governments. Balance of trade considerations.
16 25. Since many issues are complicated by too many variable and unknown factors for accurate analysis, is there an effective mechanism to make significant pilot experiments in the social and economic areas before finalizing long range policies? 26. What are the short and long range implications of the interconnection decision? 27. Domestic satellite issues. Services in the continental USA. Services to Alaska and Hawaii. Impact on industrial growth. 28. Information pollution. Much of the information transmitted over communications facilities is irrelevant and wasteful. Should any limits be set to the amount of information transmitted? If so, who enforces it? 29. Compatibility and commonality between civilian and military needs in telecommunications. How much "hardening" and redundancy of plant is appropriate from the standpoint of possible natural disasters? How much for military emergencies? 30. Is there a good case for Federal subsidy to enhance the competitive advantage of the U.S. telecommuni- cations industry over those in other countries - keeping in mind that telecommunications are government-controlled abroad? 3l. Multi-national companies in telecommunication and electronics. Their nature and characteristics. Are they advantageous from the long range U.S. standpoint? 32. Are the U.S. patent laws as significant as originally intended, in the present telecommunication industry? Consider from the standpoint of industry, inventor and public interest. What improvements are in order? 33. Impact of anti-trust laws on the telecommunications industry and the balance of trade. 34. Impact and importance of the telecommunications industry on the U.S. economy. Armig G. Kandoian Telecommunications Consultant Ridgewood, New Jersey
17 RESEARCH ON SPECTRUM, PROPAGATION AND RELATED AREAS OF TELECOMMUNICATIONS TECHNOLOGY I. General The electromagnetic spectrum is a very important resource which is vital to modern telecommunications in the broadest sense. Much has been written on the importance, use, regula- tion and exploitation of this resource in the public interest. From our standpoint it is only necessary to recognize that the demand for radio frequency spectrum is large and growing every day as individuals, industry and institutions find more users for this resource. In some cases, the use of the spectrum resource is indis- pensable for the services rendered and no reasonable alterna- tives are possible. Such, for example, are the uses of the radio spectrum in navigation aids, mobile communications, satellite communications and certain broadcast applications. In other cases, there are alternatives to the use of the radio spectrum, but the alternatives may be uneconomical or awkward or both. An NAE Committee on Telecommunications report* had the following to say on the growing overcrowding of the spectrum: "During the past twenty years there has been a series of spectrum management studies ... The most general and the most basic consideration evidenced in all of these studies is the indisputable fact that spectrum usage is expanding and spectrum space is limited. This combination makes eventual scarcity inevitable. The question remains, however, as to exactly when this scarcity will reach critical proportions and what effects it will have on the nation." Thus, with the resource limited and the demand growing, a serious challenge is presented to scientists and engineers to The Application of Social and Economic Values to Spectrum Management, Committee on Telecommunications, National Academy of Engineering, June l970.
l8 delay and, if possible, postpone indefinitely, the day when the spectrum is saturated and no additional services can be provided without very serious interference problems between services. Actually the use of the radio spectrum has evolved over the years in a rather haphazard manner and the method of assigning spectrum and allocating channels for the various services is far from optimum from the standpoint of the present state of the art. II. New Research With additional research and improved technology it can be said with some confidence that perhaps another order of magnitude improvement in density of services is possible within the presently allocated spectrum without undue destructive interference between services. With further expansion of the spectrum to shorter and shorter wave lengths, much more usable spectrum space can be available for telecommunications and related applications. Significant research effort which would help postpone indefinitely the extreme scarcity or saturation of the radio spectrum may be classified under the seven headings listed below. The National Science Foundation (NSF) might consider soliciting creative research ideas in each area and sponsoring the best of these not duplicating ongoing work. l) Spectrum extension 2) Modulation theory 3) Propagation 4) Antenna systems 5) Noise and interference 6) Social and economic aspects of spectrum utilization 7) Management of spectrum Following are some general comments on each area followed by a list of research topics submitted by knowledgeable workers in the field. A. Spectrum Extension This type of research is basic. The object is to have more of the valuable resources by expansion of the usable
19 upper limits of the electromagnetic spectrum. This would include the generation, precision measurements, component developments of means for modulation, transmission, reception and general control of radio frequencies through the infra- red, optical and ultra violet regions. Much of the upper reaches of the spectrum may actually have more important uses for medical and industrial applica- tions, in addition to communications. A great deal of this type of research is actually going on in various industrial and university laboratories. It may only be necessary for the NSF to do a watchful monitoring of these activities to ensure that vital gaps are not left in the general knowledge and that what data is developed is not monopolized unduly for proprietary advantage, but becomes pub- lished or generally available in the public interest. B. Modulation Theory The overall objective of this area of research is to find more efficient modulation schemes which will permit maximum in- formation transmission and reception per unit of spectrum occupied. This involves information theory, adaptive communi- cations techniques and more sophisticated modulation methods than used in much of the crowded spectrum at the present time. Though there is the possibility of substantial improvement in the efficient use of the spectrum following this line of research, it must be kept in mind that it will not be practical to implement this potential improvement because of long standing channel assignments and investments in systems and equipment. However, the results will be applicable to new services in the not yet crowded portions of the spectrum, and in due course may provide a basis for revision and more efficient assignments in the presently well established areas. C. Propagation The propagation of radio waves in the earth's atmosphere is an extremely complex phenomenon which has attracted researchers from the time of Marconi and Heaviside. Much has been dis- covered over the years, but much still remains either unknown or not fully predictable.
20 At the low end of the radio spectrum there is need for detailed data to be able to evaluate controversial huge pro- grams like Sanguine. At higher frequencies, in the HF band, the propagation is still not as predictable as we would like for many important applications. There is, however, the very intriguing fact, experimentally established, that the iono- sphere can be modified artificially by high power directed beams to enhance desirable properties for special applications. More intensive work in this area is almost certain to be pro- ductive. In the UHF, SHF and the higher regions of the spectrum there are unknowns with respect to the effects of different types of rain and also refractive index layers in clear atmos- phere which in some bands raise havoc with the "expected" line of sight propagation. There is need to gather and coordinate worldwide experi- mental data on propagation as a function of time, wavelength, weather conditions, and geographic area. There is also need to record and establish how effectively the spectrum is in fact used, as against how it is legally assigned and intended for use. On the theoretical front it would be very useful to develop an overall unified engineering theory of propagation to encompass all important physical phenomena such as refrac- tion, diffraction and scatterings. D. Antenna Systems The state of the art in antenna systems is sufficiently well advanced so that any reasonable requirement can usually be met. However, for the sake of completeness it should be mentioned here that further work may be necessary in certain important applications to confine radiation to the desired path and avoid or minimize minor lobes and back and side radiation. Related to this is need for very precise stabili- zation of antenna beams to prevent extremely narrow beams from shifting off target, a capability particularly important in satellite communications. E. Noise and Interference In any telecommunications system, the ultimate limitation of the sensitivity is determined by the nature and general level of the circuit noise in the frequency band used.
21 Noise may have many sources including the ever present thermal noise, along with atmospheric, solar, galactic, as well as man-made noise. Considerable research has gone into the study, measure- ment and characterization of the different types of noise. But more will be required if we are to optimize telecommunica- tions systems. It is particularly important in some rather unusual applications, such as at very low frequencies in sub- marine, deep water and deep mine communications circuits. F. Social and Economic Aspects of Spectrum Utilization The proper use of spectrum resources in the public interest obviously involves some continuing research in technology as discussed above. But public interest implies evaluation and trade off analysis involving social, economic, legal, regula- tory and other factors. This calls for some objective inter- disciplinary research where there are no established yardsticks or criteria for optimization. So it is doubly a research problem. Research of this type could best be done in universities, where the requisite talent in the social, economic, legal and other fields (in addition to the technical talents) are available and can be brought together to address specific research problems. Hopefully they can be fully objective and not be swayed by political and industrial pressures, and the results of their analysis can be made fully available to everyone. G. Management of Spectrum Finally, the method of managing the spectrum, in both its commercial and government aspects, has in fact been carried out fairly effectively in the past, as evidenced by the phenomenal growth of spectrum use and the telecommunications industry. However, as the spectrum becomes more crowded with users, the problems multiply. It is important, therefore, to study and consider critically the desirability of some new and improved approaches to the assignment of the spectrum, its use and management. Such research and studies might anticipate problems and find innovative solutions before the difficulties
22 get hardened by large investments and established positions which will be very difficult to modify. III. Research Topics* Following are some specific research items suggested for consideration by workers active and knowledgeable in this field (no priority is intended by the sequence of the listing) l. Characterizing propagation through dense, random, inhomogeneous media, such as re-entry plasmas. 2. Multiple scattering in random media composed of many coupled discrete objects, such as heavy precipitation. 3. Coupling of large antennas to the propagation medium, such as in tropospheric microwave links. 4. Development of a unified engineering theory of propagation to encompass all important physical phenomena, such as refraction, diffraction, and scattering. 5. Signal distortion and bandwidth limitations of various propagation media, such as tropospheric line-of- sight, over-the-horizon scatter, ducting, optical and micro- wave guides, and thru-the-earth. 6. Non-linear effects in wave propagation with regard to high power transmissions and inter-modulation effects. 7. Analyses of wave propagation on optical fibers, taking into account boundary roughness, bends, kinks, and inhomogeneities of the dielectric. 8. Consideration of non-electromagnetic methods in communications, such as seismic signaling. Research is underway in many of these areas. The listing means that additional effort may be productive, particularly to maintain the U.S. technological leadership. Many of the suggestions are from staff members of the Institute of Telecommunications Sciences, Department of Commerce, Boulder, Colorado.
23 9. Ionosphere modification and applications. l0. Radio technology applied to seismology and earth- quake prediction. 1l. Radio technology applied to tornado detection and prediction. l2. Research on clear atmosphere refractive index layers. (Applicable to radio propagation and air navigation) l3. Rain and water vapor classification and effect on transmission. l4. Surface reflection, roughness and vegetation, and influence on propagation ducts. Propagation in modern urban environment (tall buildings) and dependence on frequency band. Air-sea interaction. A. G. Kandoian Telecommunications Consultant Ridgewood, New Jersey
24 THE EFFECT OF STANDARDS ON RESEARCH AND DEVELOPMENT IN TELECOMMUNICATIONS I. Introduction The setting of standards in any industry is intended to simplify equipment, to make it less costly and to use resources more efficiently. There are many cases, however, where standards are a difficult compromise and where the techniques for standard setting are not always optimized. If one studies the effect of setting standards on the research and development process as it applies to the tele- communications field, it is quite obvious that standards have a noticeable effect. On the positive side, the establishment of standards narrows the areas for productive research and thus permits a concentration of effort not otherwise possible. On the negative side an agreement on standards can close off a fruitful technical approach before the value of that approach may have been demon- strated. One therefore hopes that standard setting bodies are technically well informed, have a world-wide knowledge of developments and are truly objective in the establish- ment of any new telecommunications standards. A renewed attention is being given to the establish- ment of a one-world concept in telecommunications. The ever increasing availability and constantly decreasing costs of international communications present a startling new challenge to evolve and optimize a one-world system. Satellite transmission and other recent technical developments are creating a new urgency for a stronger attack on the problem. Because of the advanced technology already available in the United States and our posture of continuing leadership in telecommunications research and engineering, the balance of trade could be favorably influenced by fostering the one-world concept. Speaking as part of a technical community, the scientists involved with research and development usually establish their own criteria for effective standards.. Those criteria involve, at the very least, seeking a standard which incorporates the best technical solution known at the time. In addition, that best technical solution should be the basis for further growth and not stand as a roadblock against continuing development or the introduction of evolving newer technologies. It should also permit the efficient use of technical manpower, avoiding duplication of research and engineering, and should, by engineering guidelines, be considered logical.
25 There are often many other interests -- political, commercial, national, regional â which have vested interests in the establishment of standards. In many cases these considerations lead to standards which are less than effective as measured by logical R&D criteria, or by the one-world criterion. Standard setting can be utilized as a means of restricting markets,or conversely of promoting world trade. Standards can be used to restrict communications, to hinder further growth, or to foster regionalization. Often, standards setting bodies involved in the tele- communications field are confronted with the need to arrive at a compromise solution which best reflects the many interests which they perceive. It is often true that the resulting standards have significant effect upon the R&D community and sometimes appear contrary to the best technical and engineering practices. Added to the above factors is the dilemma of setting standards too early, in which case the best technical solutions have often not yet been demonstrated. On the contrary, setting standards too late has a tendency of obsoleting investments that have been made in behalf of a system which was not adopted. The too-early-too-late problem can stifle innovation on the one hand and waste resources and investments on the other hand. Weaker groups often conclude that, in the absence of a standard, there are advantages to deferring research and development just to avoid that potential obsolesence. Sometimes because of the non-technical interests that are reflected in the final standards, a situation eventually arises where multiple standards are adopted which conflict with one another. Although such a result is technically undesirable and often economically disad- vantageous, it does arise in satisfaction of political, commercial or other interests. When it occurs it is con- trary to the one-world concept of telecommunications evo- lution and it offends the logical sense of the engineering community. Most of the circumstances surrounding the development of standards which have been outlined previously are found in case studies which may be used as examples. One case study centers around the development and adoption of the standards for the format for Pulse Code Modulated (PCM) Telecommunications Carrier Systems. This particular example also illustrates one other factor unique to tele- communications standards in the United States. The Bell System as the dominant force in telecommunications in the U.S.A. can, and often has adopted standards which, of
26 necessity, are copied by other carriers and organizations which must provide compatible equipment. This puts a special burden upon the Bell System to consider carefully the effect of Bell standards on the remainder of the U.S. common carrier network, and additionally, the effect upon world standards. In the PCM case study a number of these points are apparent. From this case, it is possible to draw the conclusion that a more thorough study of the process by which standards are established might be helpful. It is possible that a thorough review of the interrelationships between the American National Standards Institute (ANSI), the Electronic Industries Association (EIA), the Federal Communications Commission (FCC) in the U.S., and Con- sultative Committee on International Telegraph & Telephone (CCITT) and Conference Europeenne des Postes et Telecom- munications (CEPT) would be useful. And, of course, it is important to factor in the various standards committees of the Institute of Electrical & Electronics Engineers (IEEE) and the scientific and technological know-how they can bring to bear on standards. The problem is clear - a more orderly procedure would be helpful and would improve the effectiveness of Research and Development. It could have a substantial effect upon the balance of trade problems. The steps leading to a solution are not entirely clear and should be the subject of further study. II. Telecommunications Standards in the U.S.A. The telecommunications industry in the United States, dominated almost entirely by the common carriers, has been able to manage its own standards activities very effectively. Standards and specifications for transmission and for equipment have been established primarily by the Bell System and have been sufficiently flexible so that interface problems between operating companies have usually not been overly difficult. Under this system, an obsolete crank ringer telephone connected to a hand switched 20-party local switchboard can talk to the World Trade Center in New York City. The interconnects take place for the most part automatically through long lines trunks and then into the receiving exchange. The two parties are totally unaware of the sophisticated system through which their conversation has been directed to provide them with this ability to communicate. Until recently, interconnection of any equip- ment or system into the common carrier has been only with
27 permission of the common carrier. With the new interconnect rulings, however, additional standards will have to be developed in order to protect the common carrier network. As noted above, internal standards for the telephone industry have gradually evolved through the years - and the system has worked well. Since most of the advanced communications technology has come from the Bell System,it was natural that Bell's specifications were adopted. In a few cases Bell specifications did not become industry standards where they did not affect performance or inter- connect capability, or where an independent manufacturer or user found a more efficient or economical approach. In the non-telephone communication industry we have a different situation. Lack of an adequate set of TV per- formance standards, or lack of agreements between broad- casters on color standards even today give marked differ- ences in quality from station-to-station or even from camera-to-camera. The viewer often has to become his own "standards" monitor by adjusting dials to make green faces natural only later to have to readjust at the next commercial. For cable TV systems, there are no standards governing CATV operations. Local communities must accept whatever the operator provides in the way of signal level, signal- to-noise ratio, color quality, cross-talk, without any recourse to a set of standards for performance. IEEE has committees working in this area, but standards have not been established. This is an example of where late standard setting can be costly. A few years hence when installations become large, the late adoption of standards might obsolete terminal and transmission equipment and everybody could suffer â manufacturer, operator, and user. III. Telecommunications Standards in Europe European countries have taken telecommunications standards quite seriously. Although not often the case in telecommunications, standardization in Europe has sometimes been used to protect national markets from outsiders, and there are cases where the introduction of unique national standards have perhaps been a matter of national pride. Television broadcasting in Europe now has three standards, the PAL system, the SECAM system and the 405 line system, none of which are compatible with the U.S. Standard NTSC system. Television broadcast ranges usually span several countries so that signals from a number of stations having different standards are available for reception in many places. However, to take advantage of the variety of channels, a more expensive multi-standard receiver is required.
28 In the point-to-point telecommunications area in Europe, there would appear to be a great deal of standardization with both CCITT and CCIR having many years of experience behind them and some significant body of creditable technical achievement. In fact, however, there are still many small differences from one country to another within Europe. Although it is possible for a competent manufacturer to build equip- ment for use in more than one country, it is no accident that the multinational telecommunications manufacturing companies do have manufacturing facilities in more than one country. Even in frequency division multiplex equipment, used for long lines that cross national borders, there are significant differences. Often these will appear as alternatives given in the CCITT documen- tation. In addition, there are many details inside a system which are not standardized at all by CCITT. These are handled by the National PTT Administrations and they vary from country to country. In spite of the variances, a worldwide automatic telephone network is taking shape,although probably at greater cost than would be the case if uniform standards were a reality. IV. Pulse Code Modulation - The Case of the Multi-Standard Pulse code modulation carrier may become a classic example of the problems of adopting standards. Early standardization by Bell began in the U.S. and eventually there evolved the present TlDl,D2,D3 24 channel digital carrier system and its hierarchies. Its initial use by Bell was intended primarily as an economic and efficient alternative to FDM carrier in exchange trunking systems for short haul trunks (up to 50 miles) between exchanges in a major city to permit more voice channels in such metropoli- tan areas over existing cables. In Europe where early decisions were not necessary, digital standards were ultimately studied as part of an overall digital switching and transmission system, rather than as a carrier technique. Largely as a result of dif- ferent philosophies, Bell for the U.S. and later CEPT for Europe adopted different standards for PCM transmission. A. Bell System PCM Standards In the U.S., the Bell System pioneered in digital communication with the introduction of the Tl carrier in the early l960's. This PCM system proved quite successful, and large quantities were installed during the l960's, thus setting, through large committed investment, the first U.S. "standards" for PCM. Compatibility with this initial equip- ment dictated standards which had then to be followed by
29 succeeding transmission equipment. The Tl 24 channel system was developed solely for use on short haul exchange trunks, but field experience quickly proved the equipment had much longer distance capabilities. Therefore addi- tional development occurred and led to the planning of a PCM hierarchy to include an entire family of compatible transmission equipment. The family includes a 4 x 24 channel group of 96, operating at 6.3l2 megabits/sec, designated as T2, and higher multiples for T3 and T4 and T5. In the planning of the digital hierarchy it was quickly recognized by Bell that the Dl coding format first used with the Tl did not provide a sufficiently high grade of transmission for toll service. The principal problem existed in the quantizing noise produced by the 7-bit voice encoding pattern of the first version (Dl) . For this reason, a major change was made to an 8-bit code, and the improved equipment and new "standard" was assigned the nomenclature "Tl/D2," for reference to the D2 channel banks encoding the 8-bit code. For both versions digital transmission on the existing 22 gauge line is at the rate of l.544 megabits per second, with digital pulse repeaters introduced in the line at the normal loading coil spacing of approximately 6000 feet. Thus, the pulse rate was made the same for either Tl/Dl (7-bit) or Tl/D2 (8-bit) standards. The Tl/D2 may be used not only for the original short haul exchange trunks, but with the 8-bit format it is acceptable for long haul, and thus it becomes the basis of planning for the nation-wide switched long distance digital network in the United States. B. Other PCM Standards Elsewhere in the world PCM digital carrier equipment is now starting to be installed in quantity, though at a lower pace than in the United States. Canada is adopting the Bell System's standards and this will provide end-to- end compatibility with U.S. equipment. Japan has standards which are quite similar, but not identical to the United States. European countries have recently adopted a standard of encoding and grouping which follows a format different from that of the Bell System. As contrasted to the U.S. standard (Bell) of 24 voice channels for the Tl carrier, a European standard worked out by CEPT (Conference Europeenne des Postes et Telecommunications), uses a grouping of 32 channels of which 30 are voice, and a transmission rate of 2.048 megabits per second. In the Bell System Tl/D2 standard, signaling information is added in place of one voice bit in every 6th frame, permitting all 24 channels to be voice channels, each carrying its own signaling information. The European CEPT standard grouping, on the other hand, uses 30 out of its 32 channels for voice,
30 reserving one for framing, and the remaining channel for carrying signaling information for all 30 voice channels. This basic difference between U.S. and European standards results in equipment which is not compatible on an end- to-end basis. There are also other significant differences. At the present time, this does not create a problem since there are no PCM transmission links between North America and Europe. In the future, however, this incompatibility will cause unnecessary expense for international PCM calls and will result either in reduction to analog and reen- coding, or complex automatic translating and buffering ("transcoding") schemes. A number of other standards have also been proposed. England's BPO tried a 24-channel system, but has recently decided to go CEPT. Both France and Switzerland have tried other standards. At the present time it seems probable that both Eastern and Western European nations, including England, will gravitate toward the CEPT 32-channel stan- dard, while North America has adopted Bell's standard, with Japan using its own scheme which is similar, but not iden- tical to Bell's standard. C. International Standards in Telecommunications International standards are finally recommended by CCITT, an organization within the UN created for the pur- pose of facilitating international telecommunications, and of which the United States is a member. CCITT has reached a point where both Bell Tl/D2 24 channel and CEPT 32 channel systems will be approved as standards, although they are not compatible. D. The Dilemma The example of multistandards in PCM points up the dilemma of international standardization and the atmosphere for research and development. One can argue that PCM is an invention ahead of its time. It was born in the vacuum tube era, but became practical with semiconductors. Its introduction in the U.S. was directed toward increasing the utilization of existing short haul multiconductor cables. Its adoption in this country by the common carriers for this application required early choice of coding format and number of channels. When the Bell standards were adopted, digital long distance networks, digital local and toll switching equipment, international PCM, and satellites were not first priority considerations. In Europe, when digital transmission began to be considered and their early equip- ments developed, no great consideration was given to the long range requirement for simplifying the eventual inter- face with the North American continent and with Japan. Now
31 another requirement appears, the PCM satellite system shortly to be established will span the world and will reinforce the desirability of common standards. V. The Challenge Two new areas in which telecommunication standards can be expected to have a major effect are video tele- phone services and data services. In the former, as was the case with PCMf the first unofficial "standards" are those of the Bell Systems' Picturephone, a service which is likely to be modified and improved with changes to be expected in the standards, as customers gain experience with video systems. It is vital that CCITT, Bell and other interested groups aim for uniform worldwide stan- dards for this service in anticipation of international traffic. The cost of failing to do so can be a delay of many years in the availability of international video telephone service, as well as a more expensive service. Perhaps an even greater challenge lies in the area of pulse data transmission standards. Considering now solely the U.S. situation, we find the common carriers presently providing for pulse data transmission on the voice network through the use of modems. These devices at the sending end convert data pulses to tone bursts. The tones are transmitted in exactly the same way as analog voice signals; then are reconstituted into the pulse data at the receiving end. Modems are currently in use or under development for many different pulse rates up to 50 kilobits per second. The lower rates (up to 4800 bits per second) can be accommodated on the switched network, the higher rates are non-switched services. There are already nearly 300 versions of modems and the number is growing. Additionally, pro- vision is being made by the common carriers for a digital data network which will not use modems and which will transmit pulse data at even higher rates; 56 kb/sec in l974 and higher rates approaching about l megabit per second in the future. When one considers the anticipated problems of computer interconnection, taking into account the variety and numbers of I/O devices and peripherals, together with the growing legions of different computers, all steadily demanding higher operating speeds, the challenge for standardization is clear. It should be noted in passing that, in addition, the modem approach, and the digital data network which the carriers offer to subscribers for pulse data service,
32 the carriers transmit pulses for internal use. Dial pulses at l0 per second and PCM carrier pulses at l.544 and 6.3l2 megabits per second are standards relating to the operation of the network and are not offered to/ nor are they suitable for, direct customer use. Finally, we must eventually face the computer inter- connection problem. If computers in different locations around the country are to talk to one another efficiently at very high bit rates with minimum buffering, it is apparent that standards should be developed which make computer cycle rates compatible with communication system bit rates. No agreement now exists even among computer manufacturers for standardizing at these high rates, and the communications compatibility problem is therefore moot at this time. It would appear, however, that the best interest of the nation will not be served by the computer manufacturers adopting one set of standard rates for high speed synchronization, while the common carriers independently optimize the data communications network against a different set of require- ments . VI. Conclusions With the rapid growth of international telecommunica- tions facilities there is need for improved procedures for standardization. What was at one time purely a U.S. prob- lem, or purely a European problem, now becomes a world problem. International direct dialing standards are only a minor example of the growing requirements for a one-world basis for telecommunications standards. The standards for satellite communications have not yet proven a major problem, but the introduction of PCM techniques can change that situation. Planning for video telephone and data standards presents a challenge of the highest order. Finding a more objective procedure for setting standards is a most desirable goal. The procedure itself is subject to study and recommendation and merits the attention of U.S. interests. A method for the channeling of worldwide R&D results to the groups responsible for establishing and coordinating standards should also improve the quality of the standards. With improvement in international standards, the U.S. technological leadership in telecommunications could be better reflected in a more favorable U.S. balance of trade.
33 Three potential areas for study might prove fruitful in supporting U.S. representatives in future telecommunica- tions standards discussions. l. Investigate the possibility of determining the key elements in a proposed standard. 2. Investigate methods of better utilizing key element information and other resources. 3. Investigate the estimated extra costs of multiple standards to include: duplication of RrD & E, interface equipment, and the like. Determine also the penalty in fidelity arising from the adoption of multiple standards. Lee L. Davenport President, GTE Laboratories, Inc. Stamford, Connecticut
