By default, TracerPlus is set to read in HEX mode and will read any RFID tag. TracerPlus does have the ability to convert HEX to ASCII at the time of reading however if a tag is not encoded in an ASCII friendly format and you are trying to read in ASCII mode, it could show up as random, odd characters.
Be sure to check how your RFID tags are encoded and what data you are expecting to read from the tag. You can set TracerPlus to read in HEX or ASCII mode at a session level by navigating to the Session in your TracerPlus Desktop project and clicking on the Data Capture section. Set the EPC tag format drop down to your desired format of HEX or ASCII, then redeploy the project to your handheld.
For more information regarding HEX vs ASCII, see the below article on the subject: