Star Micronics SP300 manual MA current loop option, RS-422A option

20 mA current loop (option)

Pin no.	Signal name	I/O	Function
		direction
9	TTY TXDR	—	Indicates the ground side of the data signal
			of 20 mA loop current.
10	TTY TXD	OUT	Transmitted data of 20 mA current loop.
17	TTY TXDR	—	Indicates the ground side of the data signal
			of 20 mA loop current.
18	TTY RXDR	—	Indicates the ground side of the data signal
			of 20 mA loop current.
19	TTY RXD	IN	Received data of 20 mA current loop.
23	TTY RXDR	—	Indicates the ground side of the data signal
			at 20 mA loop current.
24	TTY TXD	OUT	Transmission data of 20 mA current loop.
25	TTY RXD	IN	Reception data of 20 mA current loop.

RS-422A (option)

Pin no.	Signal name	I/O	Function
		direction
9	SD (+)	OUT	Transmitted data
10	SD (–)	OUT	Transmitted data
17	RD (+)	IN	Received data
18	RD (–)	IN	Received data
19	CS (+)	IN	When the host computer is set to standby
			for data transmission, this signal changes to
			“SPACE”.
			(In this instance, the printer does not check
			the signal.)
23	CS (–)	IN	When the host computer is set to standby
			for data transmission, this signal changes to
			“SPACE”.
			(In this instance, the printer does not check
			the signal.)
24	RS (+)	OUT	Data transmission request signal. When the
			printer is ready to receive data, this signal
			changes to “SPACE”.
25	RS (–)	OUT	Data transmission request signal. When the
			printer is ready to receive data, this signal
			changes to “SPACE”.

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