How to read serial port data? - Full guide for technicians

If you want an in-depth analysis of how to read RS232 data from a COM port, then this article is just for you.

While serial ports have lost popularity with the introduction of USB and other high-speed data transfer technologies, serial ports are still very much in use in specialized industries and they play an integral part in networking laboratory equipment and other specialized scientific instruments. Serial port equipment needs testing and debugging, so COM port reader is a very popular request from technicians.

How to read data from a serial port?

If you make use of serial devices, you need to be able to constantly monitor and observe all port activity. The information can range from event notifications, system status messages and any other messages that can help to troubleshoot should a problem arise with the hardware. The information is also a helpful tool for device installation steps.

Serial port reader software - Serial Port Terminal

The Advanced Serial Port Terminal is an essential com port reader for anyone looking to access and interpret data from serial ports. This versatile, session-based tool enables users to connect with any serial port-equipped device for examination, troubleshooting, or debugging purposes. Unlike the basic Windows Terminal, it offers enhanced functionality, allowing for the sending and receiving of data in various formats (ASCII string, binary, octal, and hexadecimal) via a serial connection, and enables redirection of input/output data streams to specific files. It also provides capabilities for modem setting adjustments and more.

To effectively read serial port data using the Advanced Serial Port Terminal, users can modify serial port configurations without the need to disconnect and reconnect, fine-tune settings like baud rate, data bits, parity, stop bits, and flow control, and save incoming bytes for future examination among other features. To commence reading your serial port data, simply install Advanced Serial Port Terminal and choose the appropriate port. For reading data transmitted to a remote end via the serial port, activating the "Echo" function is necessary. This can be done by clicking the "Echo" button on the toolbar or adjusting the option under the "Appearance" tab in Preferences. The status of the "Echo" command (enabled/disabled) is indicated on the Status bar.

Read COM port with Serial Port Monitor

Alternatively you can try another software to read the serial port data. Serial Port Monitor is an easy-to-use tool for recording all communications to and from your serial COM ports. If you are using RS232, RS422, or RS485 COM protocols, you will be able to monitor and record all port activity.

The Serial Port Monitor offers a professional-grade solution for those wondering how to read the COM port, available with either a Professional or Company license. This feature, known as "Send dialog", facilitates the opening and closing of serial ports, real-time adjustment of serial port settings, and the dispatch of data in various numeral systems (binary, octal, decimal, hexadecimal) as well as in string form. Additionally, users can choose files containing binary data to send in segments, enhancing the com port reader's utility and flexibility.

If you have a standard version of Serial Port Monitor you can view the read data from an RS232. You just need to take a couple of steps:

1. Launch Serial Port Reader and select “Session -> New Session” from the Session menu option. You can also click Ctrl+N.
2. A list of view options is displayed in the “New monitoring session” window. Choose the views that suit your requirements.

   Table view - show all the I/O request packets (IRPs) in a simple table view

   Use Line view to display a detailed list of all requests passed through a particular serial line

   Dump view – shows data passed through the serial line

   Terminal view - display all data in a text console in ASCII characters

   Modbus view displays all data sent and received using Modbus Protocol with RTU (Remote Terminal Unit) mode or ASCII option

   You are not limited to one view, you can “Select All” to choose all the available options
   Use the “Select none” button to deselect and reset all previous selections.

3. Click the “Start monitoring now” or “Start in new window” checkbox in the “New session options” section of the window.
4. Capture options allow you to choose which events you want to record. The options are Create/Close, Read/Write, and Device Control. You can click one or all of the options.
   
   
5. To start monitoring, click the “Start monitoring” button. A new monitoring window with all the various views selected in step 2 will be displayed.
   
   
6. You would want to save your session so that you can refer to the logs and analyze the recorded data. To save your session, select Session -> Save session / Save session as ... from the main menu. There is also a “Save” icon on the toolbar, or simply press Ctrl + S to save your session.
   
   

The understanding of serial protocol

In order to read and analyze serial port data, there are a number of terms and concepts that you should be familiar with around the RS232 protocol. From understanding electrical voltages to pinouts, having this knowledge will make reading serial data from a com port and analyzing all the monitored data that much more meaningful.