Serial Port Interface

The pinouts for this interface are as follows:

Pin	DTE	DCE	Description (DTE)
1	—	5V	Not used
2	RXD	TXD	RXD (receive data) input to the printer.
3	TXD	RXD	TXD (transmit data) output from the printer.
4	DTR	DSR	DTR (data terminal ready) output from the printer — controls when the host may send data.
5	GND	GND	Circuit ground.
6	DSR	DTR	DSR (data set ready) input to the printer.
7	RTS	CTS	RTS (request to send) output from the printer -- always in the ACTIVE condition when the printer is turned on.
8	CTS	RTS	CTS (clear to send) - Not used by the printer.
9	5V	—	+5 V @ 0.75 A - FET Circuit current limited.

When XON/XOFF handshaking is selected in the printer driver, data flow is controlled by the ASCII control codes DC1 (XON) and DC3 (XOFF). The DTR control lead will have no effect.

The printer is configured as data terminal equipment (DTE). To connect the printer to other DTE devices such as the serial port of a PC, use an RS-232 null modem (crossover) cable. Table 1 shows the required cable connections.

Connecting the Printer to a DTE Device

DB-25S Connector to DTE Device (PC)		DB-9P Connector to Printer		DB-9S Connector to DTE Device (PC)		DB-9P Connector to Printer

When the printer is connected using its RS-232 interface to data communication equipment (DCE) such as a modem, you must use a standard RS-232 (straight-through) interface cable. The figure below shows the connections required for this cable.

Connecting the Printer to a DCE Device

DB-25S Connector to DCE Device		DB-9P Connector to Printer		DB-9S Connector to DCE Device		DB-9P Connector to Printer