VMS Help — PEEK Watching Init and Finish Sequences, Keywords GR
The GL and GR keywords take one of the following keyword values:
G0, G1, G2, G3. E.g. CHARACTER_SET=(GL=G0,GR=G2).
GR=G1 outputs "<ESC>~".
GR=G2 outputs "<ESC>}".
GR=G3 outputs "<ESC>|".