One of Serial Port Monitor’s key features is that it monitors COM ports without opening them, thus letting them be used by other applications.

If you are able to start a monitoring session, but no data is displayed in the visualizers, the possible reasons are:

  • The port you are monitoring is closed, meaning that no data can pass through and no communication can occur.

    Solution: Before starting a new session, make sure that the port was opened by some application. For opening the port you can use, for instance, Putty, HyperTerminal, or Serial Port Monitor’s Send dialog.

  • The port is open, but no data is sent to it.

    Solution: Make sure that the attached serial device is functioning correctly and is actually sending the data you are expecting.