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Bar Coding: Basics

Character Entry Error Rate. Keyboard entry 3/1000 OCR Scanning 1/10,000 Bar Code (code 39) 3/10,000,000. Bar Coding: Basics. Bar codes are alternating sequences of dark and light bands which encode data for reading by machines.

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Bar Coding: Basics

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  1. Character Entry Error Rate Keyboard entry3/1000 OCR Scanning1/10,000 Bar Code (code 39)3/10,000,000 Bar Coding: Basics • Bar codes are alternating sequences of dark and light bands which encode data for reading by machines. • In many applications, bar coding is preferred to entering data manually to computers, because of its relative speed, accuracy, convenience and cost effectiveness. • The width and the number of the bands define the different character sets according to many coding schemes.

  2. Typical barcode system • INCLUDE: • bar code generating software • laser scanners - unmanned or hand-held • decoding capability - digital signal processor • appropriate computer interface - RS-232 • programming capability for scanners - locally or through host computers.

  3. Bar Coding: Coding Schemes • The first (ANSI) standard coding scheme, Code 2 of 5 (or code 25) was introduced in 1972 which means that there are 5 bars per character, two of which are wide. • Since then Code 25 (now used mainly on airline tickets and photo processing envelopes) was joined by over two dozen schemes. The most important are • UPC-A (Universal Product Code): 12-digit code used in North America for consumer items (European code is different) • Code 39 (Code 3 of 9): 9 bars, any ASCII character, most common in manufacturing, hospitals and military applications • UCC/EAN-128: variable-length : any ASCII character, most common in labeling shipping containers • ISBN: 10-digit, book publishing and distribution

  4. Separator (2 bars) 60707 00113 10 Digits x xxxxx || xxxxx x Item Parity check (4 bars) MFR Code Key (4 bars) 0 all branded items 2 random weight item (2 bars per digit) Coding Schemes: UPC-A • Was introduced in 1973 and became the standard for the retail industry in North America. The European code, EAN/JAN-13, is an extension of UPC to include country of origin code. • The code consists of 10 digits (two bars/digit): • Not as tolerant of scanner error and versatile as Code 39

  5. * I S A T 3 0 3 * Coding Schemes: Code 39 (MIL-STD-1189) • Was introduced in 1974 and is the most widely-used bar code in industrial and military (MIL-STD-1189)applications. • The original code represented digits, upper case letters and 8 special symbols only, but later it was extended to represent all basic ASCII characters. • Each character is represented by 5 bars and 4 spaces (9 symbols), three of the bars are wide (thus 3 of 9): Start/ Stop Start/ Stop

  6. Bar Coding:Sensors • Light (visible or infrared) pens • Pen moves on a fixed label at certain speed to scan code • Close contact and limited angular orientation • least expensive of sensors • Hand held scanning gun with visible light • Light source scans fixed or moving label • tolerant of movement of object or gun • larger scanning angles than pens • more expensive than light pens • Fixed light scanners • a fixed light source automatically scans codes on moving items • most common in automatic control of material handling systems • most expensive

  7. Bar Coding: Typical Manufacturing Applications • Item identification, counting and tracking • Reliable on-line data collection and verification • Information coding, storage and recall • Automated materials handling (conveyors) and control • Distribute work orders and process instructions • Order fulfillment, shipping and receiving • Time and attendance management • Inventory (materials and products) tracking and control • Quality control • Work center capacity and schedule management

  8. Reports Inputs to Standard MRP System Exhibit Aggregate production plan Firm orders from known customers Forecasts of demand from random customers Master production schedule (MPS) Engineering Change Notices (ECN) + - Inventory transactions Material Resource Planning System (MRP) Bill of material (BOM) file Inventory record file Production scheduling and Control ....

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