Serial Port Monitor 9.0 [Build 9.5.589Released: November 16, 2023


  • Users can now select whether to monitor a slave or master device when enabling the Modbus view option for their monitoring session.
  • The Modbus view settings - the device type (slave/master) and data protocol (RTU/ASCII) - are now included in the exported session file.
  • The selected Modbus device type (master/slave) and data protocol (RTU/ASCII) are now displayed in the title of the monitoring session visualizer window.


  • Issues with displaying license activation information and Trial license status in the Serial Port Monitor "About" window.


  • Support for Windows XP and Windows Server 2003.

Serial Port Monitor 9.0 [Build 9.0.556Released: August 3, 2022

  • Changed: Serial Port Monitor is now offered on a subscription basis.
  • Added: support for Windows 11 and Windows Server 2022.
  • Added: support for Windows on Arm.
  • Added: the possibility to monitor COM ports with long and custom names.
  • Improved: administrator rights are no longer required to start the software.
  • Improved: Serial Port Monitor reinstallation does not always require a system reboot.
  • Fixed: an issue with opening COM ports that are found after starting the software.
  • Fixed: an issue with enabling the Dump View data redirection option from the main menu.
  • Fixed: a crash when closing Serial Port Monitor on Windows 11.
  • Fixed: issues with saving values specified in the field "Add after packet to transmit" in the Send Dialog settings.

Serial Port Monitor 8.0 [Build 8.0.410Released: June 10, 2021

  • Lots of minor fixes and improvements.

Serial Port Monitor 8.0 [Build 8.0.388Released: July 8, 2020

  • Improved: overall performance and stability.
  • Improved: support for USB to COM port adapters.
  • Improved: stability of the monitoring session when processing large data streams.
  • Improved: data processing speed.
  • Fixed: minor issues of the interface.
  • Lots of minor fixes and improvements.

Serial Port Monitor 7.0 [Build 7.0.342] Released: January 16, 2018

  • Added: search on hitting CTRL+F when comparing sessions.
  • Added: navigation to the next/previous difference with Alt+↓/Alt+↑ when comparing sessions.
  • Improved: Unicode label is now added at the beginning of the file when exporting to Unicode.
  • Fixed: incorrect displaying of data in some locales.
  • Fixed: rare cases of text not being sent from the terminal window if the text and system locales differ.
  • Fixed: crashing on opening some session files.
  • Fixed: incorrect exporting of binary data with a null character to raw format.
  • Fixed: inability to export data from the command line if specifying the full file path.
  • Fixed: joining data from different ports into one packet in Dump view.
  • Fixed: inability to apply the ‘Whole word only’ option when searching.
  • Fixed: issue with driver loading on systems with ‘Secure Boot’ enabled.

Serial Port Monitor 7.0 [Build 7.0.312]
Released: April 19, 2017

  • Added: Modbus protocol (RTU and ASCII) decoding.
  • Added: new view for Modbus protocol.
  • Added: separate filters for Modbus protocol.
  • Added: Windows Server 2016 support.
  • Added: monitoring session comparison.
  • Added: an ability to reproduce session back to the serial port.
  • Added: 64-bit GUI version (the monitoring will not be interrupted when the process occupies too much RAM).
  • Added: selection synchronization between the views.
  • Added: the “Comments” column for the Table view.
  • Added: an ability to toggle filters on and off from the toolbar.
  • Added: an ability to create a new file for data redirection when the monitoring is inactive.
  • Added: displaying the total read/written data statistics in the status bar between the first and the last highlighted IRPs in the Table view.
  • Added: displaying serial port settings changes in the Dump view.
  • Added: the option to choose what data is displayed in the Dump view: binary, ASCII, port settings.
  • Added: displaying the monitoring session statistics in the status bar, when the session file is opened.
  • Added: an ability to apply filters to the specific serial ports.
  • Added: displaying data for the Write event in the Table view that application tried to write to the port, apart from actually written data.
  • Added: an ability to disable the auto scrolling for the Terminal view.
  • Added: the command line option that allows appending data to a file instead of overwriting it.
  • Added: a progress bar when saving the monitoring session.
  • Improved: the IRPs in the Table view now show the transcript hint from the Line view.
  • Improved: “New session” window redesign (all available ports are displayed right away).
  • Improved: the main window title now displays which serial ports are being monitored currently.
  • Improved: monitoring session files can be opened with the double-click.
  • Improved: monitoring session files can be opened by drag-and-dropping them onto the Serial Port Monitor window.
  • Improved: the serial ports in the “New session” windows are now sorted by the port number instead of name.
  • Improved: the monitoring does not start automatically when the monitoring session file is opened.
  • Improved: “Data representation” option will not allow setting more than 100 characters per line now to improve the performance.
  • Fixed: memory leak when “Keep last 100 IRP” is enabled (now this option prevents the high memory consumption during the long monitoring).
  • Fixed: built-in terminal hanging when the hardware flow control is enabled and the serial port on the other side of the connection is not opened.
  • Fixed: incorrect displaying of 0d 0a characters.
  • Fixed: hanging when new serial ports appear in the system.
  • Fixed: disabling of the Terminal view menu options when it is closed.
  • Fixed: applying Capture options when the monitoring process is started.
  • Fixed: crashing on closing Serial Port Monitor during the opening of large monitoring session files.
  • Serial Port Monitor ActiveX installation alongside Serial Port Monitor is no longer allowed.

Serial Port Monitor 6.0 [Build 6.0.235] Released: July 17, 2015

  • Fixed: visualizers selection wouldn’t apply when starting a new session via command line
  • Fixed: issue when options set via menu (View – Windows) applied to the wrong view
  • Fixed: Send dialog options in Preferences were not applied after saving them
  • Fixed: some cases when new events were not captured after monitoring restart
  • Fixed: Read/Write data filter in Preferences failed to apply to Terminal view

Serial Port Monitor 6.0 [Build 6.0.215]
Released: February 10, 2015

  • Added: possibility to add several ports for monitoring in one session
  • Added: requested length value is now displayed in Table and Line views
  • Added: possibility to switch between the corresponding input/output packets in Table view (“Pair” context menu option)
  • Added: possibility to save layout of all views’ windows
  • Added: possibility to skip capture of Device Control events to avoid high memory usage
  • Improved: nonpaged memory load was substantially decreased to avoid system hanging
  • Improved: port monitoring proceeds even if serial port disappears from the system and then reappears
  • Improved: settings at new session creation are preserved now
  • Fixed: BSOD during the program uninstallation after erroneous monitoring start
  • Fixed: issue when “merge data” option settings were not saved after the program restart

Serial Port Monitor 5.0 [Build 5.0.191] Released: May 27, 2014

  • Added: possibility to merge data of the same type if it comes within a given time period in dump view
  • Added: data packet size is displayed in table view now
  • Added: Ctrl+A hotkey support in dump, line and table views
  • Added: name of the application which opened COM port is now specified in line view
  • Improved: ‘Clear All’ action now also resets statistics in Status bar, in addition to resetting data in visualizers. Ctrl+Delete hotkey was added for this action as well.
  • Improved: session file name is now displayed instead of port name in window title bar when loading session from file, to make concurrent running of several sessions comfortable
  • Improved: port parameters and statistics are now reset when starting port monitoring
  • Improved: port parameters in Status bar are now reset when loading session from file
  • Fixed: issue when meaning of certain fields, including StopBits/Parity, was not specified in line view
  • Fixed: issue when description was not displayed for certain requests when loading session from file in line view
  • Fixed: issue when new parity value set in send dialog was not applied in case the port was not open
  • Fixed: issue when wrong port parameters were displayed in Status bar in case setting of new values failed
  • Fixed: error during automatic check for updates at program start if there was no Internet connection
  • Fixed: issue when failed requests were not displayed in line view
  • Fixed: high CPU load if port was closed during file sending
  • Fixed: issue when file dialog was invoked if file sending was canceled
  • Fixed: issue when port name was not displayed in window title bar when entering full-screen mode in one of the views

Serial Port Monitor 5.0 [Build 5.0.125]
Released: August 20, 2013

  • Added: command-line options to configure data redirection at new session start or opening an existing one
  • Added: redirected file can be either split into a bunch of files or can be limited to user-defined size
  • Added: possibility to export raw data to a file in Terminal view
  • Added: Status Bar progress notifications for some operations, like open file or apply filters
  • Added: Alt+ hotkeys to “New Session” wizard
  • Added: Find option is available in Table view as well now
  • Added: time mark for each IRP in Dump view; read/write successive events are not combined into a single event any more
  • Added: automatic check for updates
  • Greatly improved: events monitoring speed
  • Improved: redirect and export engines were fully rewritten
  • Improved: the GUI was sped up and memory consumption reduced for Table, Line and Dump views
  • Improved: large .spm session files are now processed much quicker, consuming less CPU
  • Fixed: search is based on the current selection now, even if the selection changed during the process
  • Fixed: issue with search textbox not being in focus in Find dialog
  • Fixed: illogical Tab key behavior in “New Session” wizard
  • Fixed: applying wrong interval at start of command looping
  • Fixed: Find option works in “up” direction as well now
  • Fixed: export errors for certain events in Line view
  • Fixed: cases of erroneous data export in Dump view
  • Fixed: wrong end-of-line export in Terminal view
  • Update: Windows 2000 is not supported anymore

Serial Port Monitor 4.0 [Build]
Released: October 12, 2010

  • Added: Windows 7 and Windows Server 2008 support
  • Fixed: issue on Windows 7 with starting monitoring serial port, which is already opened
  • Fixed: captured data mismatch if compared in Dump and Line views
  • More stable and bug-free monitoring of large data streams transmitted through serial ports

Serial Port Monitor 4.0 [Build]
Released: February 12, 2008

  • Added: internal driver is launched automatically and administrator rights are not required to start monitoring serial ports now
  • Added: ability to input any baudrate in Send dialog
  • Improved: overall application stability while using multiple-processor systems
  • Improved: stability with enabled DEP in Windows Vista
  • Fixed: several issues with signed drivers in Windows 64-bit editions
  • Fixed: minor bug in Preferences dialog
  • Plenty of internal bugs and glitches fixed

Serial Port Monitor 4.0 [Build]
Released: March 13, 2007

  • Serial Port Monitor is completely compatible with Windows Vista
  • Now you can send files and automatically loop commands execution by sending directly from the new completely refreshed Send dialog
  • Added: aliases – pre-defined sequence of commands assigned to a short name for faster execution
  • Added: ability to automatically add data before and after packets to be transmitted
  • Table View log can be exported and redirected to file in CSV(Comma Separated Values) file format
  • Refreshed, polished and more flexible user interface
  • Serial Port Monitor and all of its internal drivers are now digitally signed
  • Major monitoring driver modifications
  • Improved: overall application’s stability and speed
  • Software licensing policy has changed: Standard and Professional editions of Serial Port Monitor have been introduced
  • Plenty of internal bugs and glitches fixed

Serial Port Monitor 3.0 [Build]
Released: November 29, 2006

  • Several fixed that refer to data view when receiving data of 0 length
  • We improved automatic drivers installation in both: 32 and 64-bit environments
  • Some critical minor enhancements
  • Some speed issues resolved

Serial Port Monitor 3.0 [Build]
Released: August 8, 2006

  • Improved: overall application’s stability and speed
  • Improved: several interface enhancements
  • Fixed: memory leaks due to incorrect events handing
  • Fixed: monitoring session closing/saving issues

Serial Port Monitor 3.0 [Build]
Released: August 4, 2006

  • Improved: overall application’s stability and speed
  • Fixed: BSOD when closing monitored port
  • Fixed: several minor bugs

Serial Port Monitor 3.0 [Build]
Released: June 22, 2006

  • Fixed: All pointers in a code are correctly closed

Serial Port Monitor 3.0 [Build]
Released: February 8, 2006

  • Fixed: Minor issues in Dump view are fixed

Serial Port Monitor 3.0 [Build]
Released: February 2, 2006

  • Added: Ability to monitor serial ports currently opened by other applications
  • Improved: Terminal panel is now known as Send dialog
  • Improved: Send dialog allows to send strings, binary, octal, decimal, hexadecimal and mixed (hex plus strings)data
  • Added: New tab in Preferences dialog
  • Fixed: Several minor bugs

Serial Port Monitor 2.1 [Build]
Released: December 15, 2005

  • Fixed: Carriage Return character (/r) issue in Terminal View

Serial Port Monitor 2.1 [Build]
Released: November 23, 2005

  • Fixed: Line view log clearance issues

Serial Port Monitor 2.1 [Build]
Released: October 5, 2005

  • PnP requests to remove serial port device management are fixed

Serial Port Monitor 2.1 [Build]
Released: August 31, 2005

  • Serial Port Monitor now is compatible with 64-bit Windows OS

Serial Port Monitor 2.0 [Build]
Released: July 22, 2005

  • Fixed a bug in Dump view representation
  • Minor bug in Export Dump view is fixed

Serial Port Monitor 2.0 [Build]
Released: July 19, 2005

  • Added functionality to Dump view. Now it shows what file has opened or closed serial port
  • Fixed minor bugs in a driver
  • Improved program interface and performance

Serial Port Monitor 2.0 [Build]
Released: July 6, 2005

  • Added ability to monitor two or more ports simultaneously
  • Added ability to select different numeration system data representation (binary, octal, decimal, hexadecimal) and string length.
  • Advanced timestamp monitoring (date and time, time only, interval from session start, interval between events)
  • Improved status bar. Added IRP, read/write databits counters, bitrate/handflow/parity/datalenght indicators
  • Added ability to set how long IRP would be stored
  • Added ability to select/deselect Table view columns
  • Improved Terminal view
  • Fixed some bugs in a driver working in HyperThreading mode
  • Interface bugs fixed

Serial Port Monitor 1.2 [Build]
Released: March 4, 2005

  • HyperThreading issues stabilized
  • Sessions saving/loading enhanced
  • Views refresh and scrolling enhanced

Serial Port Monitor 1.2 [Build]
Released: February 8, 2005

  • Grammar corrected in some texts
  • Terminal now works in read-only mode and you will see characters only when port is open and Echo is on, vertical scroll added
  • The monitored port is now default in Terminal
  • “Clear filter” fixed
  • The number of days left in a trial version is now visible
  • Autoscrolling and line wrapping in Terminal
  • CTRL+P keyboard shortcut duplication fixed
  • *.SPM files can now be opened directly with Serial Port Monitor
  • Redirection of the view into file doesn’t lead to crash
  • Automatic scrolling in views
  • No more “Cannot load sniff driver” message
  • Double launch fixed
  • Interface refurbished under Windows 2000
  • HyperThreading compatibility enhanced
  • Monitoring while sending files more than 1 Kb does not lead to crash.

Serial Port Monitor 1.2 [Build]
Released: January 21, 2005

  • New session dialog enhanced
  • Session files opening fixed
  • Several post-release additions

Serial Port Monitor 1.2 [Build]
Released: January 20, 2005

  • Reversed registration name trouble fixed
  • Some internal descriptions corrected

Serial Port Monitor 1.2 [Build]
Released: January 14, 2005

  • Compatibility with Windows 2000 Server/Pro fixed

Serial Port Monitor 1.2 [Build]
Released: January 13, 2005

  • Bug with monitoring restart fixed
  • Some minor interface enhancements

Serial Port Monitor 1.2 [Build]
Released: January 12, 2005

  • Monitoring Session (*.spm) format added
  • Several auto-scrolling enhancements
  • CTRL+ENTER hotkey added within the terminal module
  • New “Redirect to file” feature
  • Some stabilizations and minor fixes

Serial Port Monitor 1.0 [Build]
Released: January 4, 2005

  • First official release