identifying terminal by escape codes? - test-drb@ccmp.vtda.org

14 Oct 2010

...
 The "device control" codes appear to have
their familiar uses:

DC1 = ctrl-Q = reader on
DC2 = ctrl-R = punch on
DC3 = ctrl-S = reader off
DC4 = ctrl-T = punch off 
...
 However, it isn't yet clear whether the device
being used is truly a
reader/punch, or that these codes are used for some analogous purpose
to turn on/off read/write of another device. 
That would (to me at least) seem inconsistent with my theory that this
is a dialect of Tektronix 4010 control codes - I can't work out any
sensible interpretation of the sequence
1) 1D		  Group Separator
2) 37		  7
3) 7F		  DEL
4) 20		  SPACE
5) 40		  @
6) 1F		  Unit Separator
7) 12		  DC2
8) 1D		  Group Separator
9) 37		  7
10) 7F		  DEL
11) 20		  SPACE
12) 40		  @
13) 1F		  Unit Separator
14) 14		  DC4

that would allow for lines 1-6 and 8-13 to be both graphics control
codes (positioning the cursor) and lines 7 & 14 to be turning a device
on & off.

of course, I may be tracing the execution flow wrong, and there could
be errors in the dump...

...
 > The escape sequences I see are:
>       HEX                       ASCII
> 1) 1F 26 24 <x y z> : ESC & $ <xyz>
> 2) 1F 26 27 <x y z> : ESC & ' <xyz>
> 3) 1F 26 21 <x y z> : ESC & ! <xyz>
>
> where 1,2,3 are all output at different times, with <x y z> being
> values I haven't yet determined (they are register values i.e. set at
> runtime, whereas the first 3 bytes are hardcoded) 
...
 The first value is hex 1B, of course (not 1F). 
yes - my bad!

...
 The x,y,z values apparently represent a record number
(128-byte records).
x is an ASCII digit (30 - 39 hex)
y is an ASCII digit (30 - 39 hex)
z has the range 40 - 5F hex (at sign through underscore) 