T1: A Survival Guide

Errata for T1: A Survival Guide

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The errata list is a list of errors and their corrections that were found after the product was released. If the error was corrected in a later version or reprint the date of the correction will be displayed in the column titled "Date Corrected".

The following errata were submitted by our customers and approved as valid errors by the author or editor.

Color Key: Serious Technical Mistake Minor Technical Mistake Language or formatting error Typo Question Note Update



Version Location Description Submitted By Date Submitted Date Corrected
Printed
Page Appendix D
Figure D-1

dsx1IntervalTable and dsx1FarEndIntervalTable are mis-spelled as 'internal' tables (i.e. "n" instead of "v") Also there is a reference to 'internal' instead of 'interval'

Note from the Author or Editor:
Commenter is correct. Change the two table names in Figure D-1.

Anonymous   
Printed
Page 2
3rd paragraph

The date in the line "... the infant telephony market in 1861" should be changed to "1881".

Note from the Author or Editor:
Change "the infant telephony market" to "the infant telecommunications market"

Anonymous   
Printed
Page 18
third paragraph

"Transmitting understandable human speech requires using frequencies up to 4,000 kHz." should be: "Transmitting understandable human speech requires using frequencies up to 4 kHz."

Anonymous   
Printed
Page 18
3rd paragraph

First sentence occurence of "4,000 KHz" should instead be "4 KHz" (which equals 4,000 Hz, hence the error).

Note from the Author or Editor:
Change "4,000 kHz" to "4,000 Hz"

Anonymous   
Printed
Page 26
4th paragraph

The last sentence states "Superframe formatting groups 12 channels together into a single structure called a superframe...". I believe this should state that superframe formatting groups 12 _frames_ together.

Note from the Author or Editor:
The comment is correct. Replace the word "channel" with the word "frame".

Anonymous   
Printed
Page 34
3rd paragraph

Last sentence says "In mafsny case..." It should be "many""

Anonymous   
Printed
Page 47
4th paragraph two related issues

two references to the range as multiples of 133 feet; the math is wrong - 4*133=532, 5*133=665. In first sentence reference is made "0-655 feet" in second sentence reference is made "400-533 feet, and 534-655 feet"

Note from the Author or Editor:
Weirdly, the standard refers to multiples of 133 feet, but then proceeds to divide up short haul LBO into not-quite-even multiples of 133 feet. No, the math doesn't work out. Yes, this is how products are often built.

Anonymous   
Printed
Page 64
2nd paragraph, last sentence

The last sentence of the second paragraph should be changed. It reads: "One of the most common applications of SDLC was to link 3,270 terminals to mainframe frontend processors." It should be: "One of the most common applications of SDLC was to link IBM's series 3270 terminals to mainframe frontend processors."

Anonymous   
Printed
Page 112
3rd paragraph

Is: "Not all vendors default to PPP encapsulation on serial links, but serveral do not." Should be: "Not all vendors default to PPP encapsulation on serial links, but several do."

Note from the Author or Editor:
The suggested sentence replacement in the comment is perfect, especially because it fixes a typo.

Anonymous   
Printed
Page 128
Link Integrity Verification IE in Figure 10-12

The Link integrity verification ID value changed from 00011001 binary (0x19) to 00000011 binary (0x03). The former value was specified in ANSI T1.617-1991, while the latter was adopted as part of the deltas in ANSI T1.617a-1994. (I don't know whether this was to fix a typo or to align with ITU-T Q.933 Annex A.) Note that the correct value is shown in Table 10-3 at the top of pg. 130.

Note from the Author or Editor:
Change the value of the link integrity verification IE from "0011001" to "0000011".

Anonymous   
Printed
Page 159
first paragraph

"Incoming call. As in the ground-start signaling method, the CO begins by setting the incoming B bit to one, ...." I believe this should read as "...the incoming B bit to zero, ..." as shown in figure A-14. Also, the author does not state/explain that in step 2 the PBX sets the B bit to 0 as also shown in figure A-14.

Note from the Author or Editor:
Change the first sentence in the "incoming call" paragraph to read "..the CO begins by setting the incoming B bit to zero, ..."

Anonymous   
Printed
Page 160
1 sentence under section titled "Record Keeping for Later Problems

Change first word of first sentenance from "n" to "In".

Note from the Author or Editor:
Correct! The first word of that section should be "in", but the leading capital letter i is missing.

Anonymous   
Printed
Page 172
Figure B-6

According to the text beneath the figure, among the six boxes in the figure, received packets are supposed to be indicated by shaded boxes while unreceived packets are indicated by white boxes. But all six boxes are shaded.

Note from the Author or Editor:
This is a mistake in the figure translation. My original sketch had shaded boxes 1, 4, and 6. 2, 3, and 5 are lightly shaded. The best way to fix this is to change the text below figure B-6 to read: "In Figure B-6, packets that have been received and are in the reassembly queue are indicated by dark boxes (packets 1, 4, and 6), and packets that have not yet been received are indicated by light boxes (packets 2, 3, and 5)."

Anonymous   
Printed
Page 237
Paragraph in "ANSI Committee T1" section

The paragraph states that ANSI Committee T1 standards must be purchased. While this was true when the book was written, T1 standards are now available for free download from the ATIS Web site.

Note from the Author or Editor:
Change last sentence of ANSI section of Appendix F to from "ANSI standards are copyrighted and must be purchased." to read as follows: "ANSI standards are copyrighted, but are available for free download."

Anonymous