Pin D Serial Port Rs232 Cables - Brainboxes CC-431 Hardware Manual

RS232 Pinouts and Cabling
Figure 4-2. Serial Port RS232 Pin Outs.
9 Pin connector:
PIN 6 - DATA SET READY (DSR)
PIN 7 - REQUEST TO SEND (RXD)
PIN 8 - CLEAR TO SEND (CTS)
PIN 9 - RING INDICATOR (RI)
25 Pin connector:
PIN 20 - RING INDICATOR (RI)
PIN 22 - DATA TERMINAL READY (DTR)

9 Pin D Serial Port RS232 Cables.

To connect to the AT style RS232 Serial Port you will need a
cable terminating in a 9 way female D connector. It is sound
practice to use cables with screws fitted that will allow you to
fasten the cable securely to the PC card.
In general, you will need to make up a "cross over" cable to
correctly interface the PC to the RS232 port of another computer
or device. Traditionally, making up the cross over cable has been
considered a black art. However, provided you have the pin outs
and handshake requirements of both sides of your RS232
connection, the cross over cable becomes a matter of common
sense. The cross over cable is simply to ensure that the right
signals going out of one RS232 port go into the appropriate lines
of the other RS232 port.
Chapter 4 Page 36
PCI 3 Port RS232
PIN 1 - DATA CARRIER DETECT (DCD)
PIN 2 - RECEIVED DATA (RXD)
PIN 3 - TRANSMITTED DATA (TXD)
PIN 4 - DATA TERMINAL READY (DTR)
PIN 5 - GROUND (GND)
PIN 2 - TRANSMITTED DATA (TXD)
PIN 3 - RECEIVED DATA (RXD)
PIN 4 - REQUEST TO SEND (RXD)
PIN 5 - CLEAR TO SEND (CTS)
PIN 6 - DATA SET READY (DSR)
PIN 7 - GROUND (GND)
PIN 8 - DATA CARRIER DETECT (DCD)