Apple III Serial Port Cable Printer Connector Frame Ground ............(FG)...... 1 <-----> 1 .....(FG) Transmit Data (Tx) ..... 2 <-----> 3 .....(Rx) Receive Data (Rx) ..... 3 <-----> 2 .....(Tx) Request to send (RTS) .... 4 <-----> 8 .....(DCD) Clear To Send (CTS) .... 5 <-----> 8 .....(DCD) Data Set Ready (DSR) .... 6 <-----> 20 ....(TDR) Signal Ground ...........(SG)...... 7 <-----> 7 .....(SG) Data Carrier Detect (DCD) .... 8 <-----> 4 & 5 .(RTS) & (CTS) Secondary Clear To Send (SCTS) ... 19 Data Terminal Ready (DTR) .... 20 <-----> 6 .....(DSR) NOTE: This is the standard Apple Modem Eliminator cable part # A3M0019. NOTE: Use printer at 1200 Baud.