- Printers
- Laser printer
56
Lexmark 56 laser printer: parallel or rear USB port disabled
Risk level
Low
Usually safe to check without specialist tools.
Urgency
Medium
Quick answer
Code [56] on Lexmark laser printers appears as Parallel port disabled [56], Standard parallel port disabled [56], or Rear USB port disabled [56]. While disabled, the printer discards any data received through that port until you clear the message and set the port buffer to Auto.
Safety first
Stop and check this first
- Lexmark documentation notes that the printer discards any data received through the parallel or USB port while it is disabled, so you must resend the print job after setting the buffer to Auto.
- Modifying the Parallel Buffer or USB Buffer value from the control panel or Embedded Web Server automatically resets the printer to update the menu selection.
Safe checks you can perform
- Clear the [56] message on the printer control panel to resume printing
- Set Parallel Buffer or USB Buffer to Auto via the control panel or Embedded Web Server
- Verify the USB or parallel cable connection, driver port setting, and restart waiting 10 seconds
Leave these tasks to a qualified professional
- Do not attempt this professional task: Inspect the controller board port connector and link buffer memory allocation
- Do not attempt this professional task: Audit Standard USB and Parallel menu settings on the menu settings page
What a technician must be able to justify
Technician visit
These are the steps they must carry out and show you. Tick them as they work: if steps are skipped, do not accept a part swap.
These are not instructions for opening or handling the equipment yourself. They are the checks that should support a technical conclusion.
Inspect the controller board port connector and link buffer memory allocation
What they doCheck the physical rear USB or parallel port on the controller board and verify whether other link buffers or the Resource Save setting are limiting the maximum allowed buffer size.
They must show youThe condition of the controller board port connector and a successful test print through the USB or parallel port.
In writingThe findings from the port hardware inspection and link buffer memory configuration.
Audit Standard USB and Parallel menu settings on the menu settings page
What they doPrint a menu settings page to verify that USB Buffer or Parallel Buffer is set to Auto, confirm that PCL SmartSwitch and PS SmartSwitch are set to On, and switch the parallel Protocol setting from Fastbytes to Standard if parallel communication problems persist.
They must show youThe printed menu settings page showing the port buffer set to Auto and active SmartSwitch settings.
In writingThe Network/Ports menu parameters applied and confirmation that local port jobs print without error [56].
Before accepting a part or repair
Nothing has been shown yet. Do not accept a part swap based on the code alone.
Follow these steps
Note: Follow the documented order. An error code identifies the affected system, but it does not prove by itself which part has failed.
Clear the [56] message on the printer control panel to resume printing
- Who:
- You, at the Lexmark printer control panel when the [56] port disabled prompt is shown.
- How:
- Check whether the display shows Parallel port disabled [56] or Rear USB port disabled [56]. Press the select button on the printer control panel to clear the message and allow the printer to continue processing other jobs.
- Result that matters:
- The [56] message clears from the display and the printer returns to the Ready state.
- If you do not use that local port for printing, the printer continues operating normally over the network or other active interfaces.
- If you need to print through the parallel or rear USB port showing [56], remember that incoming data was discarded and proceed to set the port buffer to Auto.
- Evidence to keep:
- Exact [56] port message displayed on the control panel before clearing it.
Evidence: Lexmark MS310 User's Guide - Understanding the printer messages · Lexmark MS410 Series User's Guide - Clearing jams
Set Parallel Buffer or USB Buffer to Auto via the control panel or Embedded Web Server
- Who:
- You or the administrator configuring the Lexmark Network/Ports menu for code [56].
- How:
- On the printer control panel, open Network/Ports > Parallel or Network/Ports > Standard USB and set Parallel Buffer or USB Buffer to Auto (the factory default setting). On a networked printer, open the printer IP address in a web browser, click Settings > Network/Ports > Parallel or Standard USB, enter 2 in the Buffer field, and click Submit; the printer automatically restarts to apply the setting.
- Result that matters:
- The Parallel Buffer or USB Buffer setting is restored to Auto and the printer restarts into the Ready state.
- If the printer restarts to Ready without error [56], resend the print job from the computer to verify normal printing.
- If the buffer range for port [56] is restricted, check whether other link buffers or the Resource Save setting are limiting available memory.
- Evidence to keep:
- Printed menu settings page showing Parallel Buffer or USB Buffer set to Auto.
Evidence: Lexmark MS310 User's Guide - Understanding the printer messages · Lexmark MS410 Series User's Guide - Clearing jams
Verify the USB or parallel cable connection, driver port setting, and restart waiting 10 seconds
- Who:
- You, checking the rear ports of the Lexmark printer and the computer print dialog.
- How:
- Make sure the cable is securely attached to the matching port (matching the USB symbol on the cable with the USB symbol on the printer, or the parallel connector) and confirm that the correct port is selected in the printer driver. If needed, turn off the printer, wait for about 10 seconds, turn it back on, and resend the print job.
- Result that matters:
- The physical cable and driver port match and the printer processes the resent print job.
- If the resent job prints cleanly without showing [56], the local port communication issue is resolved.
- If error [56] returns with the buffer set to Auto and a verified cable, contact authorized Lexmark service to inspect the controller board port.
- Evidence to keep:
- Selected printer driver port and test print outcome after the 10-second restart.
Evidence: Lexmark MS310 User's Guide - Understanding the printer messages · Lexmark MS410 Series User's Guide - Clearing jams
Still not solved
If the error persists, stop here. See what the technician must do and show you.
Where this code applies
A code is meaningful only inside the right product and version context.
Primary scope
- System
- Printers
- Brand
- Lexmark
- Product type
- Laser printer
Known code variants
- [56]
- [56] Puerto paralelo estándar desactivado
- Error 56
- Lexmark 56
- Parallel port disabled [56]
- Puerto paralelo desactivado [56]
- Puerto USB trasero desactivado [56]
- Rear USB port disabled [56]
- Standard parallel port disabled [56]
What it means
In the Lexmark MS310 and MS410 Series User's Guide, message [56] indicates that the parallel port or rear USB port has been disabled (Parallel port disabled [56], Standard parallel port disabled [56], or Rear USB port disabled [56]) and that the printer discards any data received through that connection. The manual instructs you to press the control panel select button to clear the message or set Parallel Buffer or USB Buffer to Auto. Other Lexmark models may differ, and this code alone never proves a hardware component is faulty.
Warnings and stop conditions
- Lowsource verified
Lexmark documentation notes that the printer discards any data received through the parallel or USB port while it is disabled, so you must resend the print job after setting the buffer to Auto.
Evidence: Lexmark MS310 User's Guide - Understanding the printer messages · Lexmark MS410 Series User's Guide - Clearing jams
- Lowsource verified
Modifying the Parallel Buffer or USB Buffer value from the control panel or Embedded Web Server automatically resets the printer to update the menu selection.
Evidence: Lexmark MS310 User's Guide - Understanding the printer messages · Lexmark MS410 Series User's Guide - Clearing jams
Symptoms and causes
Probable causes · in order
- Parallel Buffer or USB Buffer menu setting configured to DisabledCommon
The Parallel Buffer setting in the Parallel menu or the USB Buffer setting in the Standard USB menu has been set to Disabled, which turns off input job buffering on that port.
Evidence: Lexmark MS310 User's Guide - Understanding the printer messages · Lexmark MS410 Series User's Guide - Clearing jams
- Print data sent through a local parallel or rear USB port while its input buffer was disabledPossible
A connected computer or external print server transmitted a print job over the parallel or USB cable while buffering on that port was turned off, causing the printer to discard the incoming data.
Evidence: Lexmark MS310 User's Guide - Understanding the printer messages · Lexmark MS410 Series User's Guide - Clearing jams
- Port communication or initialization mismatch between the computer and the printerLess common
An incorrect printer driver port selection, parallel protocol mismatch, or loose interface cable can interrupt port negotiation and prevent jobs from printing.
Evidence: Lexmark MS310 User's Guide - Understanding the printer messages · Lexmark MS410 Series User's Guide - Clearing jams
Virtual technician
Does 56 still appear after these checks?
Answer a few questions to narrow down the likely cause and the safest next action. Guidance only - it never replaces a professional.
Sources and technical references
- 1
Lexmark MS310 User's Guide - Understanding the printer messages
Lexmark International · official_doc
- 2
Guía del usuario Lexmark MS310 - Descripción de los mensajes de la impresora
Lexmark International · official_doc
- 3
Lexmark MS410 Series User's Guide - Clearing jams
Lexmark International · 2014 · official_doc
- 4
Guía del usuario Lexmark serie MS410 - Eliminación de atascos
Lexmark International · 2014 · official_doc
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