If your barcode scanner can successfully scan barcodes printed on product labels but cannot read Code 128 barcodes generated in Excel, the scanner is likely working correctly. The problem is usually related to how the Code 128 barcode is generated.
The Most Common Problem: Applying a Barcode Font Is Not Enough
A common mistake is to enter data into Excel and simply change the font to a Code 128 barcode font.
For example:
Original data:
123456789Simply changing the font to Code 128 may make the data look like a barcode, but it does not necessarily create a valid Code 128 barcode.
Code 128 requires the data to be properly encoded, including:
- Start character
- Data characters
- Checksum character
- Stop character
Therefore, the correct workflow is:
Original Data → Code 128 Encoding → Barcode Font → Print → Scan
A barcode font changes the appearance of characters, but a barcode encoder creates the data structure required by the Code 128 specification.
Why Does the Barcode Look Correct but Still Cannot Be Scanned?
A barcode can look like a Code 128 barcode on the computer or on paper while still containing invalid or incomplete encoding.
Common causes include:
- The original data was not encoded before applying the font
- Incorrect start or stop character
- Incorrect checksum
- Barcode printed too small
- Poor print quality
- Insufficient white space around the barcode
- Barcode stretched or compressed during printing
- Excel scaling or formatting changed the barcode
For reliable scanning, make sure the barcode is properly encoded and printed clearly at an appropriate size.
Can I Use Code 39 Instead?
Yes. However, Code 39 also has specific encoding requirements.
Code 39 commonly uses * as the start and stop character. For example:
*123456789*The * characters may be required for the barcode to be recognized.
If you use a professional barcode scanner, it may be possible to configure the scanner to automatically remove the Code 39 start/stop characters from the scanned output.
Do I Need a Special Barcode Font?
Not necessarily.
You can use a compatible Code 128 barcode font, but the original data must first be properly encoded.
You can use:
- Barcode-generation software
- Excel barcode add-ins
- Excel VBA macros
- Barcode encoder tools
- Other software that supports Code 128
For large-scale barcode printing, we recommend using a barcode generator or a properly configured Excel template rather than simply changing the font.
How Can I Generate Code 128 Barcodes in Excel?
A typical process is:
1. Enter your original data
ABC1234562. Encode the data using a Code 128 encoder
The encoder generates the required Code 128 start character, checksum, and stop character.
3. Apply the Code 128 barcode font
4. Print the barcode
5. Test it with your barcode scanner
The exact encoded string depends on the Code 128 subset and the data being encoded.
How Can I Tell Whether the Problem Is the Scanner or the Excel Barcode?
Try scanning a known-good barcode from a product label.
If the scanner reads the product barcode:
The scanner is most likely working properly, and the problem is probably related to the Excel barcode generation or printing process.
If the scanner cannot read any barcode:
The problem may be related to the scanner configuration, connection, or hardware. Please contact our support team for troubleshooting assistance.
Troubleshooting Checklist
Before contacting support, please check:
☐ The data has been properly encoded as Code 128
☐ You are not simply changing the original data to a Code 128 font
☐ The barcode contains the correct start, checksum, and stop characters
☐ The barcode is printed clearly
☐ The barcode is not stretched or compressed
☐ There is sufficient white space around the barcode
☐ You have tested a known-good barcode
☐ The scanner is properly paired with the USB cradle, if applicable
Need Help With Your Excel Barcode?
If your TEEMI scanner can read normal product barcodes but cannot read your Excel-generated barcode, please send us:
- The original data you are trying to encode
- A clear picture of the printed barcode
- The barcode font or software you are using
- An Excel screenshot or file, if available
Our technical team can help determine whether the issue is related to Code 128 encoding, Excel, the barcode font, printing quality, or the scanner configuration.
Key Takeaway
A barcode font is not the same as a barcode generator.
For Code 128, the original data must be properly encoded before applying the barcode font. Simply changing the font of ordinary text in Excel may create something that looks like a barcode but cannot be reliably scanned.
With proper encoding, printing, and scanner configuration, TEEMI barcode scanners can read Code 128 barcodes generated for factory, warehouse, inventory, retail, and other applications.
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