my question may be silly ;but may i have an aswer please?
It's not silly, people may not have personal experience transferring NJB3 to DAT (I know I don't). Theoretically, to transfer NJB3 to DAT you'd have to:
[1] copy the NJB3 files to your PC via Firewire or USB
[2] play the files back through your soundcard digital-out
[3] record onto your DAT machine
Once you complete [1], yes - you can transfer to CD for your own private use.
Good idea? Depends on whether you feel it's worth the effort. I've not come across many people who
only trade DAT. I've found most DAT traders have made the transition to SHN/FLAC trading.