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Serial port, Programmer's guide pcos series 150 communications, Serial port features – Star Micronics 150 User Manual

Page 127: Serial port pin-out

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Programmer's Guide

PcOS Series 150

Communications

Serial Port

12/14/99

Rev G

Page 117

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
detect

Not used

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
control signal to
host

Output

Pin 4

DTR

Data terminal
ready

Printer ready to receive data
(follows buffer)

Pin 5

GND

Signal ground

Disable printer
control from host

Input

Pin 6

DSR

Data set ready

Not used in standard printer
(configurable)

Ready and/or flow
control signal to
host

Output

Pin 7

RTS

Request to
send

Printer ready to receive data
(follows buffer)

Flow control from
host

Input

Pin 8

CTS

Clear to send

Not used in standard printer
(configurable)

*Strapable 12 V or
DTR

Output

Pin 9

SSD

Secondary
data

Not used in standard printer
(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