Virtual Integrated Design

More RS232 Monitoring Hook-up Diagrams

There are different ways to connect RS232 devices for monitoring. Using RS232 Com Tool and/or RS232 Com Monitor to monitor RS232 communications allows us to use a combination of mother board port(s), ISA/PCI card port(s) or USB port(s) to set up a reliable and easy system.

There are a few reasons we may want to monitor RS232 communications.
The first reason may be that we are developing a program that uses RS232 to communicate with an embedded device. For debugging we could simply use RS232 Hex Com Tool to send commands from the PC to the embedded device and observe the response in the receive window.
After the embedded device is debugged and we are satisfied with it's performance we will need to observe the communication between the PC application and the embedded device with our monitoring application. We can use either RS232 Hex Com Tool or RS232 Com Monitor for half duplex but we must use RS232 Com Monitor (with 2 available com ports) for full duplex monitoring.
For this step we can either use the PC running the code we have developed to also do the monitoring or use an additional PC or laptop to monitor the communication. This decision depends on personal preference, the amount of data being transmitted and the speed. In general if data is constantly being transferred and the baud rate is over 56K a separate PC should be used. If we use the same PC to monitor our RS232 communications the setup could look like one of the following:

The first image shows that we are monitoring with full duplex capability and com port 1 is the port that our application is using. Com ports 2 and 3 could be either ISA/PCI ports or com port USB device(s), any combination can be used. One advantage to a USB system is the RS232 hub and com cable assembly are hot swappable, that is, they can be connected or disconnected from the PC/laptop on the fly and the PC/laptop doesn’t have to be shut down. For full duplex we need to use RS232 Com Monitor to show both sides of the communication.
The second image shows half duplex being used. For half duplex communication we just need two com ports, one port for the application we are developing and the other monitoring. With this setup we can use RS232 Hex Com Tool for monitoring both transmitted and received data.

Another reason we might have to monitor RS232 data is that we already have an RS232 system in place but it is not functioning properly and we need to trouble shoot it. The following images show different setups showing the PC as the device used to run either RS232 Hex Com Tool or RS232 Com Monitor to view the data.

The last images show how USB can be used for our setups.



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