Read Code 39 Barcodes in C# Quickly and Easily

What Does a Standard Code 39 Barcode Look Like?

This image contains a standard Code 39 barcode. Notice how the barcode displays its encoded value both as bars and as human-readable text below. This dual representation is typical of Code 39 barcodes in industrial and logistics applications.

What Code Do I Need to Read Standard Code 39?

```cs :title=Reading Standard Code 39 Barcodes / :path=/static-assets/barcode/content-code-examples/how-to/read-code39-barcode.cs / using IronBarCode; using System;

BarcodeReaderOptions options = new BarcodeReaderOptions() { // Tell the reader to only look for Code 39. ExpectBarcodeTypes = BarcodeEncoding.Code39 };

// Read barcode(s) from the image file using the specified options var results = BarcodeReader.Read("code39.png", options);

// Loop through each BarcodeResult found in the image foreach (var result in results) { // Print the decoded string value of the standard Code 39 barcode Console.WriteLine(result.ToString()); }

Specifying the expected barcode type significantly improves reading performance. IronBarcode doesn't waste time looking for other barcode formats, which especially benefits batch processing of large image sets. Learn more about optimizing barcode reading performance with our [reading speed options guide](https://ironsoftware.com/csharp/barcode/how-to/reading-speed-options/).

### What Output Should I Expect?

<div class="content-img-align-center">
    <div class="center-image-wrapper" style="width=50%">
         <img src="/static-assets/barcode/how-to/read-code39-barcodes/standard-output.webp" alt="Visual Studio console showing Code 39 barcode reading output with decoded value ABC-1234 and exit code 0" barcode class="img-responsive add-shadow">
    </div>
</div>

The console output shows the successfully decoded value "ABC-1234" from our Code 39 barcode. The exit code 0 confirms successful execution without errors. In production applications, implement proper error handling for cases where barcodes might not be recognized. Check out our [troubleshooting guide for unrecognized barcodes](https://ironsoftware.com/csharp/barcode/troubleshooting/barcode-not-recognized/) if you encounter issues.

<hr>

## How Do I Read Extended Code 39 Barcodes?

Reading an extended Code 39 barcode follows a similar process to standard Code 39. The key difference is setting the `UseCode39ExtendedMode` property to true.

This setting instructs IronBarcode to interpret special character pairs (e.g., +T, %O) and decode them into their full-ASCII equivalents (e.g., t, !). Extended Code 39 uses two-character sequences to represent characters outside the standard set. This makes the barcode slightly longer but enables encoding of lowercase letters, additional punctuation, and control characters.

### When Should I Use Extended Code 39?

Extended Code 39 is ideal when your application needs to encode:
- Mixed case text (uppercase and lowercase letters)
- Special characters like @, #, &, !, ?
- Control characters for data transmission
- Full ASCII character set support

Common applications include healthcare systems, document tracking, and advanced inventory management requiring rich data encoding.

### What Does an Extended Code 39 Barcode Look Like?

This image contains an extended Code 39 barcode. The value `Test-Data!` contains lowercase characters and an exclamation mark, which are only available in the full ASCII set and require extended mode.

<div class="content-img-align-center">
    <div class="center-image-wrapper" style="width=50%">
         <img src="/static-assets/barcode/how-to/read-code39-barcodes/code39extended.webp" alt="Extended Code 39 barcode showing encoded data with 'Test-Data!' displayed as the decoded output below the bars" barcode class="img-responsive add-shadow">
    </div>
</div>

### What Code Do I Need for Extended Code 39?

```cs
:path=/static-assets/barcode/content-code-examples/how-to/read-extended-code39-barcode.cs

What Output Should I Expect from Extended Mode?

Handling Multiple Barcodes

IronBarcode automatically detects and reads multiple Code 39 barcodes in a single image. The Read method returns a collection of results, allowing you to process each barcode individually. For applications dealing with sheets of barcodes or complex documents, see our guide on reading multiple barcodes.

Dealing with Poor Quality Images

Code 39 barcodes sometimes appear in less-than-ideal conditions - faded prints, skewed angles, or low-resolution scans. IronBarcode includes powerful image correction filters that can significantly improve reading accuracy:

BarcodeReaderOptions options = new BarcodeReaderOptions()
{
    ExpectBarcodeTypes = BarcodeEncoding.Code39,
    UseCode39ExtendedMode = true,

    // Apply image correction filters
    ImageFilters = new ImageFilterCollection() {
        new SharpenFilter(),
        new ContrastFilter(),
        new BrightnessFilter()
    }
};

BarcodeReaderOptions options = new BarcodeReaderOptions()
{
    ExpectBarcodeTypes = BarcodeEncoding.Code39,
    UseCode39ExtendedMode = true,

    // Apply image correction filters
    ImageFilters = new ImageFilterCollection() {
        new SharpenFilter(),
        new ContrastFilter(),
        new BrightnessFilter()
    }
};

Performance Optimization

For high-volume barcode reading applications, consider these optimization strategies:

1. Specify exact barcode types - Always set ExpectBarcodeTypes to avoid unnecessary scanning
2. Use appropriate reading speeds - Balance speed and accuracy based on your needs
3. Process images in parallel - Utilize multi-threading for batch processing
4. Pre-process images - Apply corrections only when necessary to maintain performance