I have an Epson TM-T88II receipt printer, with a DB-25 connector. I connected it to my Debian machine with a pl2303 USB converter. I configured the printer using the following command:
stty -F /dev/usbTTY0 9600 ixon raw
Printing single lines does not work, such as
echo "Hello world!" > /dev/ttyUSB0
but printing large amounts of text works, with the following command:
yes > /dev/ttyUSB0
So the printer does work, but it seems that it starts printing when the buffer is full.
How can I print individual lines of text or images, without first fulling the buffer?