Star Micronics 150 manual Serial Port Features, Serial Port Pin-out

Programmer's Guide	PcOS Series 150	Communications
		Serial Port

Serial Port

Serial Port Features

The serial port features are as follows:

Baud rates	300, 600, 1200, 2400, 4800, 9600, 19.2K
Bit patterns	8-bit, no parity; 8-bit odd; 8-bit even; 7-bit no parity; 7-bit odd; 7-bit even
Flow control	DTR and XON/XOFF

Table 14 Serial bit rates

It should be noted that the 7-bit, no parity is in fact an 8-bit format. The implementation of the hardware UART in the Intel 8051 family will not allow a true 7-bit, no parity format. If the host provides a true 7-bit, no parity format, it must be configured with two stop bits.

The Series 150 Printer has a 64-character high-speed buffer before the main system buffer. This high-speed buffer allows the printer to operate at high serial data rates while printing. Because no data is evaluated in this buffer, the printer will have a delayed response to inquire requests and [CR]’s in one-line operation. This has a significant effect on one-line mode operation.

Serial Port Pin-out

Not connected	Input	Pin 1	DCD	Data carrier	Not used
				detect
Used in printer	Input	Pin 2	RX	Receive data	Commands/data to print
Output to host	Output	Pin 3	TX	Transmit data	Return data
Ready and/or flow	Output	Pin 4	DTR	Data terminal	Printer ready to receive data
control signal to				ready	(follows buffer)
host
		Pin 5	GND	Signal ground
Disable printer	Input	Pin 6	DSR	Data set ready	Not used in standard printer
control from host					(configurable)
Ready and/or flow	Output	Pin 7	RTS	Request to	Printer ready to receive data
control signal to				send	(follows buffer)
host
Flow control from	Input	Pin 8	CTS	Clear to send	Not used in standard printer
host					(configurable)
*Strapable 12 V or	Output	Pin 9	SSD	Secondary	Not used in standard printer
DTR				data	(provides power to peripheral)

Table 15 Serial port pin-outs

Because both the host and the printer are DTE's (Data Terminal Equipment), they use the same serial port pin-outs. If the cable that is used to connect the host to the printer is a pin-to-pin interconnect, it will not work. For this reason, a null modem or turn-around cable must be used to interconnect the host and the printer.

Signal levels

The serial interface meets EIA RS-232 requirements.

Logic 1 -15 V to -3 V: mark = off

Logic 0 +3 V to +15 V: space = on

12/14/99 Rev G Page 117