thought of the day
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30 Questions, 30 Class Periods, 30 Answers It wasn’t unusual for a student to drop into my office,...but this student’s reason for dropping in was unique. - PowerPoint PPT PresentationTRANSCRIPT
IT 327 - Schweber Chap 16 1
Thought of the Day
30 Questions, 30 Class Periods, 30 Answers
It wasn’t unusual for a student to drop into my office,...but this student’s reason for dropping in was unique.
The student began by saying, “I thought you would be interested in knowing how your class has helped me. I enjoyed studying the Book of Mormon, but I also had some problems I needed help with. So I came up with a plan. I wrote down a question for each class period. Then I prayed about the question and went to your...class.”
The young man showed me the questions he had written down: 30 questions, 30 class periods, 30 answers. I noticed that many of the answers to his questions had nothing to do with the material I had been teaching! But this student had sought the Lord in prayer and had come in faith to my class, expecting the answers. And he had received an answer to every question! I realized that the Spirit had led him to find the answers to his questions.
from Ralph E. RigbyReligion Instructor, BYU
The Ensign, March 1999, p. 39
IT 327 - Schweber Chap 16 2
Schweber, Chap 16:The Telephone System
The Phone System
IT 327 - Schweber Chap 16 3
Patented by Alexander Graham Bell in 1876Means “far” (tele) “sound” (phone)Defined expectations for communication forever after
5-9’s reliability (up 99.999% of the time, or down only 1 hour out
of 100,000, or 4¼ minutes/year). BTW, 100k Hrs ≈ 11 years
Acceptable quality and understandabilityDigital voice defined by phone system
The Phone System: Origins
IT 327 - Schweber Chap 16 4
Bell calling Chicago from New York (1892) Switchboard, c. 1890Phone, c. 1890
The Phone System: about 1930
IT 327 - Schweber Chap 16 5
Switchboard Operators, c. 1930
The Phone System:
about 1930
IT 327 - Schweber Chap 16 6
SuperTrunk links
≈20-50 miline-of-sight2-20 GHz
100-1000 Mbps
IT 327 - Schweber Chap 16 7
Local Loops
IT 327 - Schweber Chap 16 8
The Phone System: about 1950
IT 327 - Schweber Chap 16 9
Central Office
The Phone System: about 1950
IT 327 - Schweber Chap 16 10
The Phone System: about 1950
IT 327 - Schweber Chap 16 11
Leased, Conditioned, or Dedicated Lines (vs POTS)
IT 327 - Schweber Chap 16 12
DTMF
IT 327 - Schweber Chap 16 13
Features
IT 327 - Schweber Chap 16 14
Echo Cancellation
IT 327 - Schweber Chap 16 15