Handshaking Protocol - Epson C824431 Mode D'emploi

Handshaking protocol

DTR and X-on/X-off handshaking protocols can be
performed under either RS-232D or 20mA Current Loop
transmission.
X-on/X-off Protocol
X-on/X-off protocol is a system in which the printer
transmits a code to the computer to indicate that it cannot
accept more data, and a second code when it is once again
ready.
The C824431/C824432 interface card sends an X-on<11>
code when it is ready to receive data, and an X-off<13>
when it is busy. The X-on/X-off signals may be transmitted
from the TXD terminal at RS-232D signal levels, or through
the TTY-TXD terminal at 20 mA Current Loop levels.
After the X-on flag has been set, data can be accepted up to
the maximum capacity of the buffer.
• Transmit timing of X-off signal
The X-off signal is transmitted when the vacant area in
the buffer drops below the specified value (typically 256
bytes; refer to your printer manual).
• Data transfer after X-off signal
Data can be sent to the printer even after the X-off signal
is transmitted as long as sufficient room for data remains
in the buffer. However, if the transmitted data exceeds
the vacant area in the buffer, it will be discarded.
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