Plans for Chapters 9 and 10
     Identification Numbers and Bar Codes, and Transmitting Information

Objectives:  Understand the formation and usage of check digits to detect, and 
in some cases correct, errors.  Particularly if you're behind the syllabus, 
these chapters should be done by hitting carefully selected topics.  UPC 
(supermarket scanning) bar codes are far more difficult than Postnet bar codes; 
they should not be attempted if you're behind the syllabus, but can be added as 
a supplement if you're on or ahead of schedule.  In fact, there are a number of 
topics you can use as supplements from these chapters. 

Day 1:
     Outline some of the examples of check digits given in the text.  
     Particularly recommended: US Postal Service, UPC, US Banking, and ISBN, 
     though others can be used. There are lots of examples here.  Memorizing 
     codes is not the idea; students should be able to read and use the 
     formulas for various check digits.  (I tell students that I will give them 
     a brief description of any code I ask for on my quiz, but they should know 
     the kinds of codes well enough for that kind of description to suffice.)

     Assignment:  Read pages 346-356, do pp. 373-374 # 6, 8, 9, 10, 12, 14, 17.

Day 2:
     Cover the Postnet bar code system, using the Postnet bar code handout.

     Assignment: read pages 357-365, do pp. 372-376 # 1, 3, 37.

Day 3:
     Discuss binary codes and encoding using parity check sums using the (7,4) 
     binary linear code worksheet. Show how the parity check is another way to 
     do the Venn diagram method.  Optionally, you can show part of tape 24, 
     notably part or all of the last 15 minutes.  It discusses the Hamming 
     code, and the HBO scrambling discussion is of interest to some of them.

     Assignment:  Read pages 379-389, do pp. 400-401 #1-6.