A:
  meaning: A-axis of machine
B:
  meaning: B-axis of machine
C:
  meaning: C-axis of machine
D:
  meaning: tool radius compensation number
F:
  meaning: feedrate
G:
  meaning: general function (see Table 5)
H:
  meaning: tool length offset index
I:
  meaning: X-axis offset for arcs
J:
  meaning: X offset in G87 canned cycle
K:
  meaning: Y-axis offset for arcs
L:
  meaning: Y offset in G87 canned cycle
M:
  meaning: Z-axis offset for arcs
N:
  meaning: Z offset in G87 canned cycle
P:
  meaning: number of repetitions in canned cycles
Q:
  meaning: key used with G10
R:
  meaning: miscellaneous function (see Table 7)
S:
  meaning: line number
T:
  meaning: dwell time in canned cycles
X:
  meaning: dwell time with G4
Y:
  meaning: key used with G10
Z:
  meaning: feed increment in G83 canned cycle