HEIDENHAIN ITNC 530 - 6-2010 DIN-ISO PROGRAMMING User Manual page 255

QS parameters (the S stands for string) are also available on the TNC
and enable you to process texts. In principle, the same ranges are
available for QS parameters as for Q parameters (see table above).
Note that for the QS parameters the QS100 to QS199 range
is reserved for internal texts.
HEIDENHAIN iTNC 530 255