PortMon is a time capsule—a perfect tool for the era of Windows 7 and RS-232 cables. If you work with CNC machines, medical devices, or industrial PLCs that refuse to die, PortMon is your best friend. It turns a black-box serial problem into a transparent, byte-by-byte conversation.
Serial ports generate a lot of internal IOCTL chatter (e.g., SERIAL_SET_WAIT_MASK ). To see only actual data:
PortMon (Port Monitor) is a classic, lightweight utility from Microsoft’s Sysinternals suite (written by Mark Russinovich). Although it is legacy software (last updated for Windows XP/7), it remains an indispensable tool for debugging serial (RS-232) and parallel port communication on older systems or within virtual machines. how to use portmon
Since PortMon is 32-bit only, here are your options for Windows 10/11:
Before deploying Portmon, you must verify your operating system architecture. PortMon is a time capsule—a perfect tool for
If you need to send the log to a vendor or colleague:
Here is what a typical capture looks like: Serial ports generate a lot of internal IOCTL chatter (e
The interface is sparse and utilitarian, typical of Sysinternals tools.
Portmon is a standalone executable; it does not have a traditional installer.
Once PortMon is open: