The communication diagnostics test is a troubleshooting tool for checking the interconnection between the printer and the host computer. When the printer is in diagnostics mode, it prints all data received from the host computer as straight ASCII characters with the hex values below the ASCII text. The printer prints all characters received, including control codes such as CR (carriage return). Here is an example of a typical test label from this test.
The test label prints upside-down.
Set the print width equal to or less than the label width being used for the test. See Print Width for more information.