COMM-TIMEOUT-ERRTM-U220

Epson TM-U220 Error: Communication Timeout Fix

A communication timeout error on the Epson TM-U220 indicates that the printer is failing to respond to command requests from the POS terminal. This is often caused by loose data cables, port assignment conflicts, or incorrect Baud Rate settings. The first recommended action is to verify the physical connection and perform a power cycle of both the POS and the printer.

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Common causes

  • 1Baud Rate mismatch between the POS application and printer settings.
  • 2Corroded or bent pins in the serial (DB25/DB9) data connector.
  • 3IRQ or COM port address conflicts within the OS.
  • 4Internal communication board damage caused by power surges.

Solutions

Diagnóstico rápido

If the printer shows 'Ready' status LEDs but your computer software returns a 'Printer not found' error, check the connection. Ensure the cable is securely plugged in and inspect it for signs of physical damage or sharp bends.

Solución paso a paso

  1. Power Cycle: Shut down both the POS and the printer, unplug the data cable, wait 10 seconds, and reconnect firmly.
  2. Check Port Settings: Open Windows Device Manager and check 'Ports (COM & LPT)' to ensure the assigned port matches your POS software settings.
  3. Dip Switch Verification: Ensure the DIP switches on the base of the printer have not been altered, which could mismatch the Baud Rate (transmission speed).
  4. Self-Test: Run a hardware self-test (hold FEED during startup) to rule out internal interface board failure.

Prevención y mantenimiento

  • Cable Management: Use cable ties to keep data cables away from traffic areas and prevent accidental yanking.
  • Driver Consistency: Stick to the official Epson-provided drivers to avoid generic Windows driver conflicts.
  • Power Stability: Plug your POS and printer into the same power conditioner to maintain consistent voltage levels across the serial interface.

Cuándo llamar a un técnico

If you have tested with a known-good cable and on a different port but the system still does not detect the unit, the internal Interface Board (IF board) may be faulty and requires professional replacement.

Ficha técnica del equipo

  • Technology: Impact Dot Matrix
  • Interface: Serial RS-232, Parallel, USB, or Ethernet
  • Protocol: ESC/POS
  • Compatibility: Windows, Linux, macOS
  • Compatible Consumable: Epson ERC-38 Ribbon
  • Recommended Usage: Retail receipt printing
  • Official drivers / firmware

Steps to follow

  1. 1

    Check connections

    Unplug and firmly reconnect the data cable, inspecting pins.

  2. 2

    Verify port

    Confirm the correct COM port is active in Device Manager.

  3. 3

    Hardware test

    Run the printer self-test to confirm it can process data.

  4. 4

    Adjust DIP switches

    Set the Baud Rate correctly as per the manual if it was changed.

Frequently asked questions

It is often caused by a loose connection, a port mismatch, or the printer entering a protected error state.

For POS systems, yes; it prevents sales, but it is usually quickly resolved by resetting the hardware.

No, consumables like ink ribbons do not influence data communication between the printer and your PC.

Keep cabling tidy, use shielded data cables, and plug hardware into high-quality surge protection.