Transferring DATS to PC via Optical Out and maintaining 48K sampling. what program allows me to do this?

Your sound card needs to have the sync set to “Optical” or “External” so that the word clock syncs to the DAT; the DAT is the master, and the sound card is the slave. Otherwise, both decks will sync to their own internal clocks, and not sync to each other.

You would need to go into Sound Forge’s audio settings, and find the panel that interfaces with the sound card, and with the sample rate, bit depth and other settings, you should see a setting called “Sync” or “Sync Mode;” the default is “Internal” so you would need to set it to “Optical” or “External” and also make sure the sample rate (48KHz) and bit depth (16-bit) are set as well…DATs are native 16-bit recorders, whereas newer digital formats (i.e. Digital Video) is 24-bit.