Epson TM-300A Operator's Manual page 63

Pin Number Signal Name
20 ER (DTR)
When the
remaining space in the receive
statusbecomes "buffer full' and this status continuous until the space in the
receive buffer increases to 20 bytes.
The TM-300A/B do not have ON-LINE/OFF/LINE switches.
The printer goes OFF-LINE in the following cases:
During and after self-test printing.
When the printer cover is open.
When the paper is fed using the paper feed switch.
When printing stops because of paper-out.
(The paper-out selected by ESC c 4)
During the period from when the power is turned on to when data reception
becomes possible after printer initialization is completed.
When an error has occurred.
When printing is stopped due to exceeding the allowable print duty cycle.
Signal Direction
This signal indicates whether the printer
output
can or cannot receive data. When DTR/
DSR control is selected, "SPACE" indi-
cates that the printer can receive data
and "MARK" indicates that the printer
cannot receive data.
The signal turns to "MARK" in the follow-
ing cases:
When the receive buffer becomes full.
l
When the printer is OFF -LINE.
l
When XON/XOFF control is selected, the
signal is always "SPACE" except in the
following cases:
During the period from when the power
l
is turned on to when data reception
becomes possible after the printer ini-
tialization is completed.
When an error has occurred.
l
During and after the self-test printing.
l
buffer
57
Function
to 10 bytes the printer
drops