When Electronic Shelf Labels (ESLs) fail to recognize barcodes—even when scanners or registers detect them—it’s often due to mismatches or limitations in how the barcode is formatted, stored, or transmitted between the POS system and the ESL software.

This article outlines common causes and step-by-step troubleshooting solutions based on actual reported cases.

Common Issue #

Problem:
The barcode scans correctly on the POS register and handheld scanners but fails to pull up data or associate correctly in the ESL system.

Root Cause Analysis #

• The POS system may transmit only the first 12 digits of a 13-digit UPC.
• The ESL software attempts to match this input against its own dataset, which may include all 13 digits, resulting in no match.
• This discrepancy causes the ESL interface to fail when searching or binding ESL tags using the barcode.

Example Scenario #

From the Conversation: #

• A user entered a 13-digit barcode: 7503034492214
• The ESL system failed to find a match.
• Resolution:
  The last digit (4) was removed, resulting in 750303449221. This successfully matched the item.

 Key Point: ESL logic works with 12-digit codes, while POS systems sometimes send 13 digits, leading to mismatch errors.

How to Resolve the Issue #

✅ Step-by-Step Guide: #

1. Check Barcode Length
   
   • If the barcode is 13 digits, try removing the last digit and re-enter it.
2. Use 12-Digit UPC Format
   
   • Many POS systems (especially U.S.-based) default to 12-digit UPCs.
   • Input only the first 12 digits into the ESL “Search by Code” field.
3. Check POS Transmission Behavior
   
   • Confirm with your POS vendor whether the system sends 12 or 13 digits.
   • If needed, ask the POS team to truncate the 13-digit barcodes before transmitting to ESL.
4. Test PLU Codes
   
   • For produce (like fruits), test using 4-digit PLU codes (e.g., 4011 for bananas).
   • Manually enter the short code in ESL if scanning fails.
5. Provide a Sample Code to Support
   
   • Send the barcode or PLU to support for  testing.
   • Support can send back a video or instruction confirming the correct input location.

ESL Input Best Practices #

• Search by Code field is the correct place to enter barcodes manually.
• Avoid pasting full 13-digit UPCs unless your POS is known to support them fully.
• If using custom barcodes (e.g., internal codes for produce), ensure consistency between POS and ESL data formats.

Vendor-Specific Limitation #

The ESL system does not limit barcode digit length itself.
Instead, it displays what the POS provides. If the POS limits it to 12 digits or omits the 13th, this must be handled at the POS level.

The ESL China development team confirmed:

• No changes can be made on the ESL interface side.
• The POS must send a compatible format for it to display correctly.

Resolution Summary #

Barcode issues in ESL are usually the result of formatting differences between POS and ESL systems. By ensuring the correct code length and entry format, and working closely with your POS provider, you can ensure seamless ESL performance across all products.