Rating: 
Summary: A Uniquely Informative Analysis of Digital Communications
Review: This is a very helpful account of both a new technology and the factors that motivated its development. The first half of Goralski's analysis provides an in depth historical perspective of standard telephonic communication. Initially I was impatient with that treatment, but I came to appreciate the significance of how the old informs the new. In the second half of the book, each permutation of the DSL architecture is treated individually in some depth. Anyone who has a need to come to terms with this sometimes confusing arena will benefit directly from Goralski's efforts.
Rating: 
Summary: Waste of time and money
Review: This is a very wordy book which dwells more on history than necessary. The technichal information presented is poorly written and lacks depth.
The best part of this book is I bought it used ..., so I didn't loose as much as I could have.
Rating: 
Summary: This guy cooks books like scrambled eggs, same effort
Review: Which is not necessarily to say that the books is wholly bad, but: it is not edited (errors, a first sign of this new craze with telecom books, where every half-cooked piece of junk is priced $50 and sold w/o any proofreading); and second, it eclectic and too high-level. I would appreciate no more long-drawn treatments of the PSTN history, and instead a heavy concentration directly on what the title of the book says it's about. So, as an introduction this book is perhaps OK, though I'm sick of reading about PSTN and how there was manual switching five hundred years ago. Well OK, no need to mince words, tell you what I actually think: I didn't like this book. And I've bought other books by the same author and he's on my black list now; I think he's a hustler plopping barely useable info together and selling it at overblown prices. He's not the only one, of course, telecoms is an area where very few good books are available, and the publishers are engaged in blatant ripoffs. I don't recommend this book, better spend more money and get Starr's book. This one could be OK if it cost (...).
Rating:
Summary: Good overview, lacking in details
Review: Writing a popular book about xDSL technology is a daunting task, but one that Walter Goralski largely accomplishes in his book "ADSL and DSL technologies." The book begins with a global view of the US telecommunications network, how the Internet is challenging this network, and what technologies are being developed to address the problems. This world view does an excellent job of placing xDSL technologies in perspective: they are solutions to digital data transport over portions of a telecommunications network designed specifically for analog voice traffic. The author has provide an excellent summary of how the American telephone network began, how it evolved, the various regulatory actions along the way, and the current state of affairs. For example, many people familiar with load coils and bridge taps know they can cause problems for xDSL technologies. Goralski explains how these devices got into the network in the first place, and the specific problems they pose for digital high-speed technologies. As part of this discussion the author describes the first analog systems, later digital systems, multiplexing and trunk topologies, different switching technologies (packet and circuit) and the first wave of digital services such as ISDN. After a brief discussion of modems, the author launches into the main subject, which is the xDSL family of products and technology. He gives a brief high-level descriptions of HDSL, SDSL, RADSL, CDSL, IDSL, ADSL, and VDSL. Up to this point the number of acronyms is relatively manageable, but once he begins discussing xDSL in earnest the acronyms emerge exponentially. Fortunately, Goralski has a list of about 250 acronyms in the back of the book. This list is especially useful later in the book where the author uses them with abandon. Though extensive, the list is not complete. For example, the acronyms PCM and STU are not included. Of course, the author says there is "really no such thing as an `STU,' at least not as a standard device." This only adds to the confusion of the use of such an acronym, and contributes to the "acronym overload" one often feels when reading this book. After the brief introduction to the xDSL family, the author devotes a full chapter each to HDSL and then to ADSL. After this, the book deals almost exclusively with ADSL-related issues (except for a chapter on VDSL at the back of the book). I was disappointed the author spent so little time describing the digital coding techniques that are so important for DSL technologies. Except for a brief mention of QAM, the author leaves his audience almost entirely in the dark as to how the digital codes work, and what are their individual strengths and weaknesses. The author goes into considerable detail (more than any other individual topic) describing the ADSL architecture and interface systems. Chapter nine, dealing with ADSL interfaces, is confusing and would benefit from more diagrams. Several subjects are discussed without proper introduction, leading to questions people might ask if they are not already familiar with the terminology. Additional topics in the book's midsection include descriptions of transport classes, bearer channels, frames, super frames, frame structure, interleaved data, and overhead. The author also provides considerable high-level detail about various configurations in which ADSL can be deployed. The book ends with three of its most important chapters. Chapter 13 describes migration scenarios from the various derivatives of xDSL to ADSL, and from ADSL to VDSL. Chapter 14 describes VDSL in more detail, since the author apparently concludes VDSL will be the ultimate mechanism by which telecommunications companies will provide truly broadband services. Chapter 15 finishes with a discussion about the major outstanding issues for DSL. These last chapters are especially useful for global thinking and positioning. Goralski discusses some market issues for the deployment of ADSL, but most of the book centers on technical topics. The author clearly favors xDSL technologies, with the apparent conclusion it will win the day over cable modems. It would be useful, however, to see more detailed analysis in this area, especially regarding cost for deployment. Though Internet access (e.g. as offered via xDSL) is important, Internet access alone will be unable to compete against true broadband services offering video on demand in addition to fast Internet access. Goralski seems to recognize this when he discusses VDSL, but even here he fails to address economic issues and whether VDSL can compete on price with cable modems. Goralski has a clear, readable style, and the book has many figures that greatly help in assimilating ideas. On the negative side, the index is inadequate. When reading my copy I used lots of colored markers and sticky tabs so I could go back and find important information. The book also has many typographical errors. Clearly, this book went to print in a hurry, though this might be somewhat unavoidable given the subject matter and rate with which technology is progressing. None of the typographical errors cause significant problems with comprehension. Most are like the one on page 12, where the word "enabled" was spelled as "abled." Overall, however, I really enjoyed reading this book. If you are just learning about ADSL technologies, or want to brush up on the subject I highly recommend it. Duwayne Anderson
Rating: 
Summary: A comprehensive overview of xDSL
Review: Writing a popular book about xDSL technology is a daunting task, but one that Walter Goralski largely accomplishes in his book "ADSL and DSL technologies." The book begins with a global view of the US telecommunications network, how the Internet is challenging this network, and what technologies are being developed to address the problems. This world view does an excellent job of placing xDSL technologies in perspective: they are solutions to digital data transport over portions of a telecommunications network designed specifically for analog voice traffic. The author has provide an excellent summary of how the American telephone network began, how it evolved, the various regulatory actions along the way, and the current state of affairs. For example, many people familiar with load coils and bridge taps know they can cause problems for xDSL technologies. Goralski explains how these devices got into the network in the first place, and the specific problems they pose for digital high-speed technologies. As part of this discussion the author describes the first analog systems, later digital systems, multiplexing and trunk topologies, different switching technologies (packet and circuit) and the first wave of digital services such as ISDN. After a brief discussion of modems, the author launches into the main subject, which is the xDSL family of products and technology. He gives a brief high-level descriptions of HDSL, SDSL, RADSL, CDSL, IDSL, ADSL, and VDSL. Up to this point the number of acronyms is relatively manageable, but once he begins discussing xDSL in earnest the acronyms emerge exponentially. Fortunately, Goralski has a list of about 250 acronyms in the back of the book. This list is especially useful later in the book where the author uses them with abandon. Though extensive, the list is not complete. For example, the acronyms PCM and STU are not included. Of course, the author says there is "really no such thing as an 'STU,' at least not as a standard device." This only adds to the confusion of the use of such an acronym, and contributes to the "acronym overload" one often feels when reading this book. After the brief introduction to the xDSL family, the author devotes a full chapter each to HDSL and then to ADSL. After this, the book deals almost exclusively with ADSL-related issues (except for a chapter on VDSL at the back of the book). I was disappointed the author spent so little time describing the digital coding techniques that are so important for DSL technologies. Except for a brief mention of QAM, the author leaves his audience almost entirely in the dark as to how the digital codes work, and what are their individual strengths and weaknesses. The author goes into considerable detail (more than any other individual topic) describing the ADSL architecture and interface systems. Chapter nine, dealing with ADSL interfaces, is confusing and would benefit from more diagrams. Several subjects are discussed without proper introduction, leading to questions people might ask if they are not already familiar with the terminology. Additional topics in the book's midsection include descriptions of transport classes, bearer channels, frames, super frames, frame structure, interleaved data, and overhead. The author also provides considerable high-level detail about various configurations in which ADSL can be deployed. The book ends with three of its most important chapters. Chapter 13 describes migration scenarios from the various derivatives of xDSL to ADSL, and from ADSL to VDSL. Chapter 14 describes VDSL in more detail, since the author apparently concludes VDSL will be the ultimate mechanism by which telecommunications companies will provide truly broadband services. Chapter 15 finishes with a discussion about the major outstanding issues for DSL. These last chapters are especially useful for global thinking and positioning. Goralski discusses some market issues for the deployment of ADSL, but most of the book centers on technical topics. The author clearly favors xDSL technologies, with the apparent conclusion it will win the day over cable modems. It would be useful, however, to see more detailed analysis in this area, especially regarding cost for deployment. Though Internet access (e.g. as offered via xDSL) is important, Internet access alone will be unable to compete against true broadband services offering video on demand in addition to fast Internet access. Goralski seems to recognize this when he discusses VDSL, but even here he fails to address economic issues and whether VDSL can compete on price with cable modems. Goralski has a clear, readable style, and the book has many figures that greatly help in assimilating ideas. On the negative side, the index is inadequate. When reading my copy I used lots of colored markers and sticky tabs so I could go back and find important information. The book also has many typographical errors. Clearly, this book went to print in a hurry, though this might be somewhat unavoidable given the subject matter and rate with which technology is progressing. None of the typographical errors cause significant problems with comprehension. Most are like the one on page 12, where the word "enabled" was spelled as "abled." Overall, however, I really enjoyed reading this book. If you are just learning about ADSL technologies, or want to brush up on the subject I highly recommend it. Duwayne Anderson
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