<cmdType>=34 (GET INKEY)
<data> contains the key pressed by the user. The character set is
selected by +CSCS command.
If the ongoing proactive command requires to the user a binary
choice (yes/no), the valid content of <data> is:
- "Y" or "y" (positive answer) and "N" or "n" (negative answer) for
"IRA", "8859-1", "PCCP437" character sets
- "0079" or "0059" (positive answer) and "006E" or "004E"
(negative answer) for UCS2 alphabet
The ongoing proactive command to require a binary choice sets bit 2
of the <cmdDetails> parameter to 1, see #STGI command.