identifying terminal by escape codes?

I just took a look at the 4010 manual, and realised that US (0x1F) selects 'alpha mode' and GS (0x1D) selects graphics mode. The very first char output by the prom is US, followed by CR/LF then '?' - it would make sense that the monitor sets alpha mode first. this sequence also looks like it is using graph mode to position the cursor, then flicks and to alpha mode to print a char, back to graphics to move cursor back to where it was, and (over)prints a different char. I haven't yet worked out whether 0x12 and 0x14 in alpha mode displays a custom graphic, but might be some kind of flashing cursor 1D Group Separator 37 7 7F DEL 20 SPACE 40 @ 1F Unit Separator 12 DC2 1D Group Separator 37 7 7F DEL 20 SPACE 40 @ 1F Unit Separator 14 DC4 not sure what these are though: 1F 26 24 <x y z> : ESC & $ <xyz> 1F 26 27 <x y z> : ESC & ' <xyz> 1F 26 21 <x y z> : ESC & ! <xyz>