ENQ/STX protocol
In addition to this XON/XOFF message, the possibility exists of request-
ing a status byte from the printer using the ENQ code (hex. 05, dec. 5).
The STX code (hex 02, dec. 2) is used to clear any error messages
(parity error, buffer overflow).
Status byte
Bit 0 – 1
Bit 1 – 1
Bit 2 – 0
Bit 3 – 1
Bit 4 – 1
Bit 5 – 1
Bit 6 – 1
Bit 7 – 0
BUSY
Off Line
Paper end
Always 1
Cover open
Buffer overflow
Parity or frame error
Always 0
STX (hex02) Clears any previous parity or framing error as well as any buffer overflow
error.
ENQ (hex05) The current printer status is sent to the host.
XON/XOFF This protocol is automatically used for data flow control and printer status
handling.
HandThr.=ON The STX and ENQ characters are not filtered out of the data stream and
control the interface in addition.
HandThr.=OFF The STX and ENQ are filtered out of the data stream and handled
immediately by the interface.
Reference manual
Interfaces
188
