Universal Serial Bus Interface - SATO D508 Service Manual

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Operator's manual (60 pages)

Programming reference manual (290 pages)

Parts list (13 pages)

Table Of Contents

Table of Contents

DB9

DB2

HOST

CTS

RTS

DTR

DSR*

This connection at the host side of the interface would depend upon the pin that is being used as

the Ready/Busy signal by the driving software. Typically, on a PC, it would be either CTS (pin 5)

or DSR (pin 6) on a DB-25 connector.

READY/BUSY FLOW CONTROL

Ready/Busy is the hardware flow control method for the serial interface on the printer. By raising/

lowering the voltage level on Pin 20 of the RS232 port, the printer notifies the host when it is

ready to receive data. Pin 4 (RTS) and pin 20 (DTR) are the important signals on the printer for

this method of flow control. The host must be capable of supporting this flow control method for it

to function properly.

X-ON/X-OFF FLOW CONTROL

X-On/X-Off flow control is used whenever hardware (Ready/Busy) flow control is not available or

desirable. Instead of a voltage going high/low at pin 20, control characters representing "Printer

Ready" (X-On =11 hexadecimal) or "Printer Busy" (X-Off = 13 hexadecimal) are transmitted by

the printer on pin 2 (Transmit Data) to the host. In order for this method of flow control to function

correctly, the host must be capable of supporting it. X-On/X-Off operates in a manner similar to

the function of pin 20 (DTR) as previously explained. When the printer is first powered on it sends

an X-Off when the "Buffer Near Full" level is reached and a X-On when the data level of the

buffer drops below the "Buffer Available" mark. When the printer is taken off-line manually, it

transmits an X-Off indicating it cannot accept data. When it is placed back on line manually, it

sends an X-On, indicating it is again available for receipt of data. If an error occurs during printing

(paper out, Time Out), the printer sends an X-Off as soon as an error condition is detected. When

the error is cleared and the printer is placed back on-line, it transmits an X-On indicating it is

again ready to accept data.

Upon power up if no error conditions are present, the printer will continually send X-On

characters at five millisecond intervals until it receives a transmission from the host.