ZD620 and ZD420 Desktop Printers User Guide

Resolve Communication Issues

Use this information to identify problems with communications and their possible causes, and try the recommended solutions.

Issue	Possible Cause(s) and Remedies
USB printer fails to install after connecting printer, before installing the printer driver.	The printer is connected to the Windows computer via USB, but it is not properly recognized by the system. A Windows-assigned printer that is incorrectly assigned cannot print a Windows test print from the selected USB-attached computer. The USB cable was attached before the correct printer drivers were pre-installed. Windows installed the Windows generic printer driver. To fix the problem: Disconnect the printer USB cable from the Windows computer. Use the Windows Search bar to search for and open Control Panel > Devices and Printers . The Zebra printer shows up under the title 'Unspecified'. Zebra printers display ZTC as a prefix to identify them easily. Click on any Zebra printers icons displayed under 'Unspecified' and delete them. If you have not previously loaded the latest Windows printer driver, load it now. See Installing the Windows Printer Drivers to add the correct drivers to the system. Plug the printer's USB cable into the Windows computer. The Zebra printer should now be added to the Printers section of the Devices and Printers window.
Label job sent to printer, but data is not transferred to the printer. A label format was sent to the printer but was not recognized. The Data indicator ( ) does not flash.	The communication parameters are incorrect. Check the printer driver or software communications settings (if applicable). If using a serial port connection, check the printer’s handshake protocol and serial port settings. The setting used must match the settings of the host computer. See Serial Interface for information on the printer’s default serial port settings. The serial cable you are trying to use may not be a standard DTE or DCE type cable, is damaged, or is too long in comparison to the RS-232 serial port specifications. See Serial Port Interface for details.
Label job sent. Printer skips labels or prints faulty content. A label format was sent to the printer. Several labels print, then the printer skips, misplaces, misses, or distorts the image on the label.	The serial communication settings are incorrect. Check the printer driver or software communications settings (if applicable). Ensure that the Flow Control settings and other serial port handshake settings match that of the host computer.
Label job sent, data transfers, but there are printing issues. A label format was sent to the printer. Several labels print, then the printer skips, misplaces, misses, or distorts the image on the label.	The prefix and delimiter characters set in the printer do not match the ones in the label format. Verify the ZPL programming prefix ( COMMAND CHAR ) and delimiter ( DELIM./CHAR ) characters. See Configuration Setting to Command Cross-reference.
	Incorrect data is being sent to the printer. Check the communication settings on the computer. Ensure that they match the printer settings.
	Incorrect data is being sent to the printer. Check the label format. See the ZPL Programming Guide for details on printer programming. For links to the manuals, see About this Guide.