Zebra KR403: Paper Jam & Communication Timeout... | terminalfaults.org

Technical Background:

Paper jam sensors on the KR403 use optical or mechanical switches. A false positive can be triggered by dust or sensor malfunction. Communication timeouts can originate from voltage drops, baud rate mismatch, damaged cables, or ESD events affecting the serial or USB interface. Signal attenuation can occur due to long or damaged cables.

Symptoms:

The Zebra KR403 card terminal printer reports a paper jam error while simultaneously experiencing communication timeouts. The printer status indicates functional operation despite the errors.

Possible Causes:

Defective paper jam sensor reporting false positives.
Loose or damaged communication cable (USB or serial).
Incorrect baud rate settings between the KR403 and the host system.
Voltage fluctuations in the power supply affecting communication stability.
Electrostatic discharge (ESD) damaging the communication port or internal components.
Software or driver incompatibility causing communication errors.

Solution:

1

Perform Safe Handling: Unplug the KR403 from the power source and communication cable.
2

Visually inspect the paper path for any obstructions or debris. Remove any visible paper fragments.
3

Clean the paper jam sensor with a dry, lint-free cloth. DO NOT use liquids.
4

Inspect the communication cable for damage (cuts, fraying, bent pins). Replace if necessary.
5

Verify the baud rate settings on the KR403 and the host system. Ensure they match.
6

Reconnect the power and communication cables. Power on the KR403 and test the printing function.
7

If the problem persists, attempt to update the printer driver on the host system. Check the Zebra support website for the latest drivers.

Safety Warning:

Avoid forcing paper through the printer mechanism. This can damage the internal components. DO NOT attempt to open the printer casing as this device contains anti-tamper mechanisms that will permanently disable the device if triggered. Ensure the device is unplugged during cleaning and cable inspection. Static discharge can damage the device electronics; ground yourself before touching any connectors.

Prevention:

Regularly clean the paper path and sensors with a dry, lint-free cloth.,Ensure the communication cable is securely connected and free from strain.,Use a surge protector to protect the KR403 from voltage fluctuations.,Implement ESD control measures, especially during dry weather (e.g., anti-static mats).,Keep the printer in a clean and dust-free environment.,Schedule periodic driver updates from the Zebra support website.

Expert Tip:

Try a different USB port on the host system. Some USB ports may have different power output characteristics. A weak USB port can cause communication timeouts. If using a serial connection, verify the correct COM port is selected in the host system's device manager.

Frequently Asked Questions

•What is the recommended cleaning frequency for the paper path?

Clean the paper path and sensors at least monthly, or more frequently if the printer is used in a dusty environment.

•What type of communication cable is recommended for the KR403?

Use a high-quality, shielded USB or serial cable that meets the manufacturer's specifications.

•How do I verify the baud rate settings on the KR403 and the host system?

Refer to the Zebra KR403 user manual for instructions on accessing and modifying the baud rate settings. The host system's baud rate settings can typically be found in the device manager or printer settings.

Zebra KR403: Paper Jam & Communication Timeout Diagnostic Report

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip:

Frequently Asked Questions

•What is the recommended cleaning frequency for the paper path?

•What type of communication cable is recommended for the KR403?

•How do I verify the baud rate settings on the KR403 and the host system?

Related questions

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip: