SerialMon SerialMon is a free RS232 serial port monitor/sniffer software for Windows. Features • Freeware • Monitors RS232 communication thru software or with simple • Protocol analyzer for ABB RP570, ABB SPA-bus and NMEA 0183 protocol • Small size Download • •, Fixes uninstall problem in v1.2-v1.4. Version 2.0 is a major update and will be released soon. Try our new & free Substation scanner software: Requirements • Microsoft Windows 2000 or later • Microsoft.NET Framework v2.0 Donations SerialMon is free. But feel free to give a donation to support the author. Announcement of new versions Subscribe to SerialMon Email: Contact us Send your comments to.

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I'm reverse-engineering a serial protocol and getting frustrated by bad tools. Does anyone know of a good, free tool for logging data to/from serial ports on Windows? Requirements: • Must be free • Must not take control of the port (i.e. Must hook the file APIs or the kernel rather than trying to open the device) • Must have some sort of filtering features • Writes either human-readable or binary logs, preferably in an easy to parse format Any ideas?

Portmon works, but its logs are difficult to work with and its filters are effectively useless; I've also tried a few commercial tools and nothing seems to fit the bill.

Com0com is open-source, so you could use that as a starting point. Another possible solution could be to pick up an rs232 splitter cable forks the serial signal to another serial port. Or yet another possibility is a Serial Sniffer program (or an open source sniffer ).