Protocol description
Data flow control XON/XOFF
The printer signals an XON (DC1 ASCII 11 hex., 17 dec.) via the TxD line
when it is ready to receive data.
XOFF (DC3 ASCII, 13 hex., 19 dec.) is transmitted via the TxD line by the
printer when
– the printer is set Offline,
– there is a paper end,
– a hardware error occurs,
– the data buffer is full.
Make sure that on the computer side a program is installed which supports
XON/XOFF control!
Data flow control
Robust XON/XOFF
See also section XON/XOFF. With Robust XON/XOFF the condition of the
printer (XON or XOFF) is transmitted by the TxD line.
Enquire printer status ENQ/STX
With the code ENQ (ENQ ASCII, 5 hex., 5 dec.) the programmer can requ-
est the printer status. Upon this request the printer sends a status byte
which can be evaluated by the programmer
.
Status byte: Bit 0 1 = BUSY
Bit 1 1 = Offline
Bit 2 0 = Paper End
Bit 3 1 = always 1
Bit 4 1 = Cover open
Bit 5 1 = Buffer Overflow
Bit 6 1 = Paritys or Frame Error
Bit 7 0 = always 0
With the STX code (STX ASCII, 2 hex., 2 dec.) the resulting possible
printer error message (parity error, buffer overflow) is cleared.
Serial interface RS232C/V.24
B - 6
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