Epson DM-D210 Technical Reference Manual page 89

Pin Signal
Number Name Direction
*1
20 DTR Output
25 RESET Input
1 Make sure to use either the RTS or the DTR terminal. Otherwise, the built-in RS-232 driver IC may be broken.
2 This signal is connected to the DTR terminal of the TM printer directly.
Signal
This indicates whether the display is ready to receive data.
 [SPACE]: The display can receive data.
DTR goes to SPACE under the following conditions:
 When the display first becomes ready to receive data after power on.
 When the self-test has ended.
 When the remaining space in the receive buffer becomes 50 bytes or
more after having been 40 bytes or less.
 [MARK]: The display cannot receive data.
DTR goes to MARK under the following conditions:
 The period from when power is turned on to when the display first
becomes ready to receive data.
 When the self-test is executed.
 When the remaining space in the receive buffer becomes 128 bytes or
less (buffer-full state).
 When DSR MARK is on, if the TM printer is selected by a peripheral device
command.
Reset signal is connected to the DTR terminal of the TM printer directly.
Function
*2
Appendix
89