Xerox Escape Sequence

Xerox Escape Sequence or XES is a page description language (PDL) developed by Xerox corporation and introduced with their 2700 laser printers in 1982. XES offers similar capabilities to Hewlett-Packard's Printer Command Language (PCL), which first appeared in 1984. XES is supported by most Xerox laser printers including the 2700. 3700, 4011, 4030, 4045, 4197, 4213, 4235, and 4700.^[1]

XES is sometimes known as UDK, from User Defined Key, the character which introduces the printer command, usually the escape character (ESC).