Lexmark T620 Service Manual page 37

4069-5XX/7XX
3. Continue pressing Return and Select until each screen of
information is obtained.
4. When the last screen displays, the original message displays.
The following is an example of how the printer shows a duplex unit
sub error code.
Byte 1
DU XX
DU XX
Byte 5
Byte 2 Byte 3
XX XX
XX XX
Byte 6 Byte 7
Byte 4
XX
XX
Byte 8
Diagnostic Information
2-9