. . . ,I hear the psk or rtty tone coming from computer . . .
If you hear PSK or RTTY tones from the computer, you _do_ have a loudspeaker inside the computer!
That built-in loudspeaker is driven by a soundcard inside the computer.
There is _another_ soundcard inside the RigExpert Tiny. You must do two things:
1. Install the "drivers" for that RigExpert Tiny soundcard on your computer. The drivers are software,
they can be downloaded from the RigExpert website.
2. After you install the driver, the computer will "see" the RigExpert's soundcard. It will probably be listed as a "USB Audio Codec", or something like that.
You must configure MIXWIN software so that it sends its _output_ (PSK, RTTY, etc) to _that_ soundcard, and does _not_ send it to the computer's internal soundcard.
Then, everything should work . . .