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3.11.6 Mode C Status and Keypad Commands
Status, key buffer contents, line count or document length data are transmitted when requested by the host.
ENQ
requests printer status and is executed when it is received.
SUB
also requests printer status but it is executed identically to an ENQ only after all previously
received commands have been executed. SUB may be used to interrupt the host and notify it
that the printer is now idle.
Printer status is a single byte that is bit significant as follows:
0 1 DP XE DJ KB BZ BA
DP = Document present. Set whenever a document is in the feed path.
XE = Transmission error. If BLOCK protocol is used, all characters received since the last ENQ will be
ignored and should be retransmitted.
If DTR or XON/XOF protocols are used the character
associated with the error will be printed as a “@”.
DJ =
Document jam. The printhead has not returned to the document edge correctly and operator attention
is required.
KB =
Key buffer. The key buffer contains key stroke information that will be transmitted upon receipt of a
DC1.
BZ =
Busy. Either printing or document movement is now occurring.
BA =
Input buffer available. At least 1000 characters of space are available in the input buffer or the buffer
is empty. Buffer operation is detailed in 3.13.1.
DC1
or DLE request keypad data. Upon receipt of either, all keypad input that has been pressed since the
previous DC1 or DLE will be transmitted. A maximum of 16 strokes can be buffered. Transmitted
characters will be one of the following:
ASCII
Meaning
0-9
Numeric keys 0-9
:
FUNCTion key
;
ENTER key
<
Either
A or
B key
=
EJECT key
?
End of buffer
The last character transmitted is always a ?. If a DC1 or DLE is received and no keys have been
pressed only a ? will be transmitted.
As numeric keys are pressed, their values are displayed on the lower display line. Pressing ENTER or
FUNCT transfers the key strokes to the key buffer. Pressing CLEAR deletes numeric key strokes
before they are transferred to the key buffer.
Function values beginning with 9 are reserved for internal printer operation and are not transferred to
the key buffer. See 3.6 to 3.9 for details of the internal printer functions.
DC2
requests line count information. Upon receipt, 2 bytes are transmitted. The first byte indicates the
number of lines and the second indicates the number of additional 1/60”
steps moved since the
document was initially registered at top edge or bottom edge.
EM
requests document length information. Upon receipt, 2 bytes representing the document length (if the
document was automatically inserted to the bottom edge) are transmitted. The first byte indicates the
number of lines and the second byte indicates the number of additional 1/60 inch steps.
