Canon BJ-10sx - Manual (Page 106)

Timing Chart
AUTO FEED XT
When this signal is low, the printer automatically feeds the paper one
line when it receives a carriage return (CR) control code. This signal is
valid only in Epson LQ mode.
INIT
INIT from the system resets the printer to it initial power-on state. The
BUSY line goes high, and any received data is printed. When INIT goes
low, the printer resets to the power-on default state.
ERROR
The printer sets the ERROR line low if it detects an error, such as out-
of-paper condition.
SELECT IN
When this signal is high, the DC1 and DC3 control codes are valid;
otherwise, they are invalid. This signal is valid only in Epson LQ mode.
The parallel interface transfers data in one direction only: from the
computer to your printer. The data path is 8 bits wide. The printer and
computer synchronize data transfer with the interface signals, STROBE,
ACKNLG, and BUSY.
When the computer is ready to send a byte of data to the printer, it puts
the byte of data on the data lines (DATA 1 through DATA 8). Then the
computer sends a STROBE pulse to the printer. The printer responds
with a BUSY signal.
When the printer receives the data, it pulses the ACKNLG line. This
signals the computer that the printer has read the byte of data into
printer memory. If the printer's buffer is not full and it can receive more
data, it removes the BUSY signal.
The timing charts that follow illustrate the data and handshake line
during transfer of one data byte to the computer. DATA 1 through
DATA 8 and the STROBE line are driven by the computer; the
ACKNLG line is driven by the printer.