Result Codes - Epson ESC/VP21 User Manual

provided below.
<char1> <char2> <char3> <AT command> <contents of S3>
Format:
e.g., DTE: +++AT<CR>
DCE: OK
NOTE: TIES requires that the three-character escape sequence be
contiguous and not repeated. The character immediately pre-
ceding the first character of the three-character sequence cannot
be the same as the escape character. Therefore, '+++AT<CR>'
is valid, but '++++ AT<CR>' is not.

2.5 Result Codes

Basic Response Codes (\V0)
Numeric Code
0
1
2
3
4
5
6
7
2 - COMMAND REFERENCE
char1=char2=char3=escape character (S2)
Verbose Code
OK
CONNECT
RING
NO CARRIER
ERROR
CONNECT 1200
NO DIAL TONE
BUSY
31