Epson C8230 User Manual

• Transmit timing 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).

F i g u r e 3 . X - o n / X - o f f t h i n g

X-ON

X-OFF

X-ON

POWER ON

Buffer capacity less

than specified value

Buffer capacity greater

than specified value

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.

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