I have this exact same issue. I have created a macro to do an 'Over-The-Air' (OTA) update for a Teensy microcontroller. The macro works fine starting with no Tera Term connection, but fails if a Tera Term connection already exists. Since the Tera Term connection is how I get status updates from the Teensy, it is always open - so I have to close it before starting the update process.
I tried using the 'testlink' command, but this doesn't find an existing Tera Term window, so is useless for this purpose.
to an existing TeraTERM window. Perhaps it could be
identified by the process number or window title.
Would this be possible?
An alternative might be to have a COM interface to
ttermpro. You could then command an instance of
ttermpro to open a new macro.