Star Micronics RS 232C Serial to Parallel Converter SPC-8K - Manual (Page 6)

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Some programmers call the XON and XOFF control codes “kiss on and kiss
off”; others call the same protocol DC1 and DC3 (for device control). Either
way, these codes are used to let your printer control the flow of data, telling the
computer when to start and stop sending data. Your printer asks to have data
held back when its memory is nearly full or when it senses an ERROR
condition.
DTR (Data Terminal Ready) protocol does the same thing slightly differently.
The printer sends a continuous high-voltage signal over the cable as long as it
can accept data, but drops the voltage to send a request to the computer to stop
transmitting.
Conversely, it is the computer that controls the data flow with the ETX/ACK
(End-of-text/Acknowledge) protocol. The computer sends an ETX control
code after each string of data, and when the printer receives that code, it sends
an ACK code back to the computer, asking for more. This protocol is less used
by modern computers because it tends not to hold back data when the printer’s
memory gets full.
Baud Rate
Baud rate indicates the speed, in bits per second, at which data is sent to the
printer. The most common setting here is 9600 or 19200.
Switch 6 Switch 7 Switch 8 Baud Rate DOS/Windows Setting
OFF OFF OFF 150 bps 150
OFF OFF ON 300 bps 300
OFF ON OFF 600 bps 600
OFF ON ON 1200 bps 1200
ON OFF OFF 2400 bps 2400
ON OFF ON 4800 bps 4800
ON ON OFF 9600 bps 9600
ON ON ON 19200 bps 19200
Setting up a serial connection on a Windows computer
Remember that the settings you make on your computer must match those you
have made using the converter’s DIP switches.
• In the Windows Program Manager, open the Main group by clicking on
its icon.