HP PCL 5 Comparison Manual page 138

Segment ID
Format/NumRanges
Range1FirstCode
Range1LastCode
Range2FirstCode
Range2LastCode
2-102 Printer-Specific Differences
The new algorithm for deciding whether or not to
counter-rotate characters (when using the Character Text
Path Direction command's vertical-rotated printing mode)
is as follows:
if (the current font contains a VE segment)
{
if(the character code* is NOT contained in
a VE range)
rotate
else
don't rotate
}
else
use the old logic
* The original character code, even if a galley character
were substituted at some point.
Examples:
Japanese ShiftJIS
V E
0 1
0x0000
0x00FF
Japanese Unicode
V E
0 2
0x0000
0x007F
0xFF61
0xFF9F
half-width latin
characters
half-width
katakana