CODING SYSTEM - Identification Methods / Techniques
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Contents
 
Introduction
Definitions of terms
Division Methods
Algorithm Methods 

    1. Weighted SUM 

     2. Codabar Method 

     3.  ISBN Code
Code 39 - Alpha Numeric
ZIP Code
Bar Codes
Other Numbering Systems
 
Introduction top
 
Purpose of Coding Techniques:
 
1. Identification of item, object  or person
 
2. Check entry error or validate entry into a computer (manual and automatic)
 
3. Reduce fraud or ease of recreating identification number
 
4. Give meaningful and useful information about an object
 
5. We live in a world of numbers and various methods of identification solve different problems
 
Trend:
 
The trend in numeric identification  methods is to use computers to generate and
 
check complex schemes for identification numbers and
 
to centralize the distribution of each identification number.
 
Table 1: Terms / Definitions top
 

TERMS DEFINITIONS
Single-position error When a number in a sequence or series is entered incorrectly
Transposition error When two or more numbers in a series are switched or move to another position in the series
ISBN International Standard Book Number
Encoding Translating data into code
Decoding Translating code into data
Id Identification, Identify etc.
Weights Numbers used in the calculation of check digits by multiplying specific series of numbers to the digits at particular position in the series
Binary Code A coding system that uses two symbols: 0 and 1
Code A group of symbols or digits that represents information and uses a set of rules to interpret the code or translate the code
Bar Code  A code that uses bars and spaces to represent information
Check Rule The steps to follow so as to validate the goodness of the entry of a series of numbers or digits
 
Division Methods top
 
These methods employ the following rules: Sum or total all the digit including the check digit
 
and  if  the total is evenly divisible by the check factor (7 , 9 or 10)
 
then the number is considered valid (this check does not validate transposition
 
errors or substitution of a digit with the check factor expect the ISBN method).
 
Table 2: Summary of Division Methods: top
 
Methods Applications Rules Advantage Disadvantage
Division by 9 1. Money Order 

2. Travelers Checks

 Total of all digits must be evenly divisible by 9 

Check digit is last digit

 1. Simple Technique 

2. Check some single-position errors

 1. Does not validate transposition errors 

2. Does not validate substation of 0 with 9 or 9 with 0
Division by 7 1. Federal Mails 

2. UPS Package 

3. Rental Cars

 Total of all digits must be evenly divisible by 7 

Check digit is last digit

 1. Simple Technique 

2. Check some single-position errors

 1. Does not catch transposition errors 

2. Does not catch substitution errors of 0 for 7 or 7 for 0
ISBN Code Coding of Books Total of all digits multiplied by know weights must be evenly divisible by 11 

Check digit is last digit and it may be a X that represents the digit 10

 1. Simple weights 

2. Check all single-position and transposition errors 

 Some computer system have difficulty reading the X at the end of some ISBN numbers
 
Examples of Division methods
 
            Example 9.1 Division by 9: Money Order
 
 
UNION BANK Money Order                        $100.00 
36700125363  
$$ 
One hundred dollars  0 cents
710000 1789     "36700125363"		 Division by 9: Rule 
3+6+7+0+0+1+2+5+3+6+3 = 36 

36/9 = 4, so pass check since division yields a whole number 

 
             Example 9.2 Division by 9: Travelers Check
 
US$50                                                 567-34803-5 
Union Bank Travelers Check
Fifty Dollars
710000 51 2        "567 34803 54"        Sign__________		 4 is the Check Digit 

What is someone had entered 567 34308 54 for the check number would it pass the check? 

Answer is yes put transposition error was made - 308 for 803. 
 
            Example 9.3 Division by 7: Mail Package
 
 
Andy Williams                                                  STAMP 
234 Main Street 
Beacon, New York 12503 

                           To: Bella Williams 
                                 5 Market Street 
                                 Chase City, Va 23924 

                                                                        67422 

 By the Division by 7 method the Postal Number 67422 when scanned by a computer passed the Division by 7 test: 

6+7+4+2+2 =21  which is evenly divisible by 7
 
 

Algorithm Methods top
 
These methods use an algorithm, a series of mathematical steps, to solve
 
or to determine the value of the check digit, i.e. the last digit.
 
Table 3: Comparison of Algorithm Methods  top
 

Method Purpose Rule Advantage Disadvantage Remarks
UPC ID Grocery products 1. Add digits in known position 

2. Triple Results 

3. Add total to sum of remaining digits 

Result should end in "0"

 1. Detect all single-position errors 

2. Detects 90% of transposition errors 

3. Tell more than id product

   1st digit id category of goods 

Next set id manufacturer 

Next set is 

id particular goods 

 Usually 12 digits
Weighted Sum Banking Industry: 

Checks Cashing

 1. Multiple each digit by a series of weights known only to particular bank 

2. Use an algorithm to process combination of weights and digits to get a specific results

 1. Detects all single-position errors 

2. Detects most transposition error 

3. Reduces fraudulent entries

 Weights are difficult to determine Only the master computer knows the weights 

Number of digits varies
Codabar Credit Cards 

Bank Accounts 

Divers License

 Rules Differ 

Use algorithm to determine results

 1. Detect all single-position errors 

2. 98% of transposition errors 

3. partially eliminate fraud

 Needs a computer to solve and assign numbers Most institutions are centralizing the creation of their number or ids so that they are unique and do more than id the person of object
ISBN ID Books 1. Multiply and add digits by know weights 

2. Total is evenly divisible by 11 

Weights: 10,9,8,7,6,5,4,3,2,1 respectively

 1. Detects all single-position and transposition errors Last check digit can be the letter X 
represents a 10		 10 - digit system including check 

1st digit tells if book was published in an English speaking country 

Next ids publisher 

Next set ids book 

Last digit is the check
 
Example of Algorithm Methods

        Example 9.4: ISBN ID Method
 
 

FOR ALL 
PRACTICAL 
PURPOSES 

FOURTH EDITION 

 
 

W.H. Freeman & Company 

ISBN 0-7167-2841-9 
 
 
 

USA 1997
 ISBN 0-7167-2841-9       10 digits 
0 - Published in English Speaking Country 
7167 - Id Publisher as W.H. Freeman & Company 
2841 -Id FAPP, the book, assigned by publisher 
9- Check digit (Sum divisible by 11) 
 
Position 1 2 3 4 5 6 7 8 9 10
Digit 0 7 1 6 7 2 8 4 1 9
Weights 10 9 8 7 6 5 4 3 2 1
Product* 0 63 8 42 42 10 32 12 2 9
* Product is the Digits multiply by its appropriate weights: e.g. 7x9 =63 

Sum of the Product = 0+63+8+42+42+10+32+12+2+9 = 220 

220 is evenly divisible by 11. 

 
 

Zip Code top  US Zip Code Link
 
This is a 5-digit US code to divide the divide the country into 10 geographic areas to speed the delivery of mail.
 
Convention:
 
e.g. 12624
 
I st digit id the Geographic areas: for example New York is 1
 
First 3 digits id the regional distribution center : for example 125 is Duchess County
 
Last 2 digits id town or city or local post office: for example 24 is Fishkill
 
Zip + 4 Code
 
The 4 extra digits can represent : Company internal mail routes, Post Office box , Internal Drop Area or Department
 
Examples of Zip Codes
 

Poughkeepsie, NY 12601
Lincoln, Nebraska 68588
Rice, Va. 23966
Green Bay, Va. 23942
 
Bar Codes top     Click here for Comprehensive Bar Code Links
 
Purpose: uses a series or group of coded lines (dark bars followed by space) to represent characteristics or id items
 
e.g. Postnet Code - Us Postal Service bar Code system that uses bar code to id zip code information
 
Series : Rule Sum of all digits must be evenly divisible by 10
 
Starting Guard Bar 8 coded digits Check digit Ending Guard Bar
 

UPC Bar Code

Universal Product Code - Check in Scanning left to right ... also contains a center set of digits
 

Guard Bar 101 Manufacturer Code 

odd numbers of ones

 Product Code 

Even Numbers of ones

 Ending Guard Bar 101
 
Other Numbering System: top

Class Discussion:

Social Security
    Example 9.5  Social Security System
 
Divers License
Passport

    Example 9.8 US Passport Services