If you plan to convert your R12i data to RINEX and submit it manually to OPUS, you need to make sure you use the proper settings in order for success. In Trimble's Convert to RINEX utility, you will nee to pick the Tools pull-down menu and select Options. In the options make sure you have the box checked to "suppress kinematic records" and make sure that for the R12i you have the default format set to "RINEX v3.04". With these settings your R12i files will successfully upload to OPUS.