Codabar

Codabar (also known as Code 2 of 7, USD-4, or NW-7) is a linear barcode format developed in 1972. While considered legacy technology, it's still commonly used in libraries, blood banks, and some logistics applications. It can encode numbers and specific special characters (–, $, :, /, +, .).

Basic Usage

import { barcode } from '@stacksjs/qrx'

barcode('#barcode', '1234567890', {
  format: 'codabar'
})

Start/Stop Characters

You can specify start and stop characters (A, B, C, or D). If not specified, A is used by default:

import { barcode } from '@stacksjs/qrx'

barcode('#barcode', 'C1234567890D', {
  format: 'codabar'
})

Character Set

Codabar supports:

• Numbers (0-9)
• Special characters: -, $, :, /, +, .
• Start/Stop characters: A, B, C, D

Advanced Options

import { barcode } from '@stacksjs/qrx'

barcode('#barcode', 'A1234-5678.90B', {
  format: 'codabar',
  width: 2,
  height: 100,
  displayValue: true,
  font: 'monospace',
  fontSize: 20,
  textAlign: 'center',
  textPosition: 'bottom',
  textMargin: 2,
  background: '#ffffff',
  lineColor: '#000000'
})

[!NOTE] Image needed: Advanced options example

Common Applications

1. Blood Banks

   barcode('#barcode', 'A1234567B', { format: 'codabar' })  // Blood type labeling

2. Libraries

   barcode('#barcode', 'A123-456+789B', { format: 'codabar' })  // Book tracking

3. Photo Labs

   barcode('#barcode', 'C12345/678D', { format: 'codabar' })  // Photo processing

[!NOTE] Image needed: Real-world application examples

Error Handling

import { barcode } from '@stacksjs/qrx'

barcode('#barcode', 'A123456B', {
  format: 'codabar',
  valid: (valid) => {
    if (!valid) {
      console.error('Invalid Codabar')
      // Handle invalid input
    }
  }
})

Best Practices

1. Start/Stop Characters

   • Always use matching pairs (AA, BB, CC, DD)
   • Be consistent across system
   • Consider scanner configuration

2. Data Validation

   // Valid examples
   barcode('#barcode', 'A1234-5678B')    // Numbers and hyphen
   barcode('#barcode', 'C1234:5678D')    // Numbers and colon
   barcode('#barcode', 'A12.34+56/78A')  // Multiple special chars

3. Print Quality

   • Maintain adequate quiet zones
   • Test with target scanners
   • Verify contrast ratios

Technical Specifications

• Variable length format
• Self-checking capability
• No check digit (but can be added)
• Bi-directional reading
• Wide/narrow bar ratio: 1:2.25 to 1:3

[!NOTE] Image needed: Technical specifications diagram

Legacy System Integration

// Old system format
barcode('#barcode', 'A1234B')

// Modern alternative (Code 128)
barcode('#barcode', '1234', { format: 'CODE128' })

[!NOTE] Image needed: Comparison with modern formats

Advantages & Limitations

Advantages

• Simple structure
• Self-checking
• Bi-directional reading
• Special character support
• Wide hardware support

Limitations

• Low data density
• No built-in check digit
• Limited character set
• Older technology

[!NOTE] Image needed: Advantages/limitations comparison chart