HP LaserJet 4100 HP PCL/PJL reference (PCL 5 Printer Language) - Technical Ref - Page 127

The PE command represents vectors in base 64 (default) or base 32 (explained under Encoding PE Flag Values and X,Y Coordinates). In parameter value data, all spaces, delete characters, control characters, as well as ASCII characters 128-160 and 255 are ignored. z No parameters - Updates the Carriage Return point. The PE command without parameters does not affect the pen's current location or up/down status. z Flag - Indicates how the printer interprets subsequent values. Flags are ASCII characters and are not encoded. The printer disregards the eighth bit of a flag (fro example, a character code of 61 and a character code of 189 both send a '=' [the absolute flag]). Table 20-22 Flag Meaning : Select Pen < Pen Up > Fractional Data = Absolute 7 7-bit Mode Description Indicates that the subsequent value is the desired pen number. A PE command without pen select defaults to the currently selected pen. Raises the pen and moves to the subsequent coordinate pair value. (All coordinate pair values not preceded by a pen up flag are considered pen down moves.)* Indicates that the subsequent value specifies the number of fractional binary bits contained in the coordinate data. Default is zero. Indicates that the next point is defined by absolute coordinates. Indicates that all subsequent coordinate pair values should be interpreted in 7-bit mode. Once you send a seven-bit flag, base 32 is used and eighth bits are ignored for the remainder of the command. * We recommend you always follow a pen up flag with a relative move of (0,0). This ensures that the next plotting coordinates are drawn. EN PE, Polyline Encoded 20-35