: Many monitors can "spy" on a port even while it is already being used by another application. Simultaneous Monitoring
These tools are lightweight and can be run directly from a USB stick without needing administrative installation. serial port monitor portable
: A widely used, free, and open-source terminal emulator that is highly portable and supports serial connections alongside SSH and Telnet. : Many monitors can "spy" on a port
Some portable tools (like HHD’s free version) can intercept serial communication between an existing application and a hardware device without needing a hardware splitter. This is done at the Windows API level. If you need this functionality, ensure the portable tool supports . ensure the portable tool supports .