It may look like garbage but it's not, you can see there is structure.
First thing to do is check that your baud rates are correctly configured as a mismatch can give you 'garbage'.
It is also likely that this is your terminal program trying to represent the bytes you are sending as ascii. If you are sending text then you should have a look at how you are 'printing' that data to the UART. If you are sending binary data then you are better off viewing it as hex or binary. If Tera Term does not give you this option then grab RealTerm
or some other terminal that does.