Serial Port Pin-Outs

 

Signal Full Name DB-9 Pin DB-25 Pin
DCD Data Carrier Detect 1 8
RXD Receive Data 2 3
TXD Transmit Data 3 2
DTR Data Terminal Ready 4 20
GND Signal Ground 5 7
DSR Data Set Ready 6 6
RTS Request To Send 7 4
CTS Clear To Send 8 5
RI Ready Indicator 9 22