Serialinterface
Pin Name IFunction I
II
1GND Printer chassis ground
I I
2TXD Data from printer
I I
3Data to printer
11
4RTS Always low
5CTS LOWwhenthe computer is ready to
transmit data
Printer ignores this signal
I11 IRCH
IIPrinter sets line low when ready to
receive data. Same signal as pin 20
20 DTR IPrinter sets line lowwhen ready to
receive data. I