Star Micronics LC-8521 Appendix C Interface Pin Outs, Parallel Interface, Serial Interface

							Checking system software settings in MS-DOS 83
Appendix C: Interface Pin Outs
Parallel Interface
Pin				Name			Function
1			STROBE				Goes low for ≥0.5∝s when active.
2				DATA0			These signals represent information for the 1st through 8th bit of parallel data,
							respectively. Each signal is HIGH when data is logical 1, and LOW when logical
3				DATA1
							0.
4				DATA2
5				DATA3
6				DATA4
7				DATA5
8				DATA6
9				DATA7
10						ACK	10∝s low to acknowledge receipt of data.
11				BUSY			Printer sets line low when ready to receive data.
12				PAPER			High when paper runs out.
13			SELECT				High when printer is on-line.
14					AFXT		Printer ignores this signal.
15							Not used.
16	SIGNAL GND						Signal ground
17		CHASSIS					Chassis ground (isolated from signal ground)
18						+5V	+5V DC output from printer
19 - 30					GND		Twisted pair ground return
31				RESET			Printer is reset when this signal goes low.
32				ERROR			Low when printing cannot continue due to error.
33		EXT GND					External ground
34 - 35							Not used
36		SELECT IN					Printer ignores this signal
Serial Interface
Pin				Name			Function
1		CHASSIS					Printer chassis ground
2						TXD	Data from printer
3					RXD		Data to printer
4						RTS	Always space
5						CTS	Space when computer is ready to send data. Printer ignores this signal.
6							Not used.
7					GND		Signal ground
8 - 10							Not used.
11					RCH		Printer sets line to space when ready to receive data. Same signal as Pin 20.
12							Not used.
13							Not used. (signal ground)
14 - 19							Not used.
20						DTR	Printer sets line to space when ready to receive data.
21 - 25							Not used.