Siemens SIMATIC S7-300 Manual page 51

Connection diagram
The figure below shows the connection diagram for a full duplex RS232 sniffer.
Port 1 taps the data of the receive line and port 2 taps the data of the send line.
Figure 7-1
If your PC has two serial interfaces, you can display the data traffic in both direc-
tions on a screen using a terminal program, e.g. HyperTerminal. A separate termi-
nal must be opened for each data direction.
However, special RS232 sniffer software products are already available, which al-
low combining the data traffic of several ports on one screen. It is thus no longer
necessary to switch between terminal windows.
Sending and Receiving SMS Messages with MD720-3
V 2.1, ID Number: 25545680
7 Further Information
51