Epson DM-D500 Technical Reference Guide - Page 65

Connectors DM-D500 (Connector) Appendix A Hardware   Pin assignments Pin Number Signal Name Signal Direction Signal Function 1 FG - Frame ground 2 TXD Output (1) In a Y or pass-through connection (*1) Transmit data to the printer (2) In a stand-alone connection Transmit data to the host 3 RXD Input Data received from the host computer 4 DSR Input Indicates whether or not the host computer or printer is ready to receive data. (1) In a pass-through connection (*1) [MARK] The printer is not ready to receive data [SPACE] The printer is ready to receive data (2) In a stand-alone connection [MARK] The host computer is not ready to receive data [SPACE] The host computer is ready to receive data 5 DTR Output Indicates whether or not the customer display is ready to receive data. (*2) [MARK] The display is not ready to receive data The display enters the MARK status in the following cases: (1) During power-on initialization (2) During self-test (3) When the empty capacity of the receive buffer becomes 128 bytes or less (the following case applies to pass-through connection only) (4) When DSR enters the MARK status on printer selection [SPACE] The display is ready to receive data The display enters the SPACE status in the following cases: (1) When power-on initialization finishes (2) When self-test finishes (3) When the empty capacity of the receive buffer recovers to 256 bytes or more from 128 bytes or less 6 SG - Signal GND 7 PS - Power supply terminal 8 PG - Return wire for power (*1) Regarding pass-through connection and stand-alone connection, see Chapter 1. (*2) When DTR signal is set to MARK status by the ESC/POS status confirmation command, this status is different from that where the signal indicates whether or not the display is ready to receive data. 65