When a return string for STT is received by TPControl that includes a single unicode character, the entire string is parsed in unicode to the NetLinx master. This is due to limitations in parsing unicode characters/strings via ICSP.
So, you will need to decode the unicode encoded string in your NetLinx code and then parse the result accordingly. This was a compromise that we had to make to ensure portablility for unicode received strings.
The details for this are included in our TPC API commands or within 'TPTransfer -> Documentation -> API commands'.