Allen-Bradley DH-485 User Manual page 17

Use Belden #8723 (or equivalent) cable to construct a cable to connect the
KF3 to a computer.
Important: The length must not exceed 50 feet, and the cable shield must
be connected to chassis ground (using Pin 1) at the KF3 end only.
There are various cabling options depending on whether or not your
application makes use of handshake signals, whether or not you are
connecting to a 9-pin serial port for an IBM AT, and whether or not your
computer uses standard IBM pinouts. Figures 2.11 through 2.16 are for
IBM computers with either 9- or 25-pin connectors. If your computer has
a different pinout, construct a cable using the appropriate signal names for
your computer.
If you are not using handshake signals, use the three wire connections
shown in Figures 2.11 or 2.12.
Figure 2.11
Three Wire Connection to IBM Computer (25 pin)
KF3
1
TXD 2
RXD 3
GND 7
Figure 2.12
Three Wire Connection to IBM Computer (9 pin)
KF3
1
TXD 2
RXD 3
GND 7
Chapter 2
Installing the KF3
Shield
Shield
Computer
3 RXD
2 TXD
7 GND
Computer
2 RXD
3 TXD
5 GND
2 9