Intermec 4630 User Manual page 238

4630 and 4830 Bar Code Label Printers User's Manual
UPC
Universal Product Code. Bar code used widely in the United States.
User-Defined Characters (UDC)
See Graphic.
User-Defined Fonts (UDF)
See Soft Font.
Variable Data Field
Bar code and text fields that change from one label to the next.
XON/XOFF
A protocol that stops the host from sending data when the printer buffer fills
up and starts it again when the buffer empties.
G-10