Epson C824431 Manual Del Usario página 19

• Transmit tinting of X-on signal
The X-on signal is transmitted when the power is first
turned on, or when the vacant area in the buffer is
greater than the specified value (typically 512 bytes; refer
to your printer manual).
Figure 3. X-on/X-off timing
X -ON
POWER ON
DTR protocol
Under this system, when the printer is turned on the DTR
enters the SPACE state, meaning that data entry is enabled.
When the rate of data reception is greater than that of
printing, the buffer gradually fills up. Once the vacant area
in the buffer drops below the specified value (typically 256
bytes; refer to your printer manual), the DTR sets the status
flag to prohibit further data entry. This flag is output
through the DTR pin (No. 20) at RS-232D signal levels, and
through the TTY-TXD pin (No. 17) at Current Loop Levels.
X-OFF
Buffer capacity less
than specified value
15
X -ON
Buffer capacity greater
than specified value