I picked up some of a exerciser box made by Century Data Systems of Anaheim, Ca. It's marked T2000B Exerciser. I THINK it might for the old Marksman T-series DC-300 tape drives. Is anyone here familar with this box or with the T-series tape drives? FWIW CDS was an early manufacturer of hard drives (1960s) and was later bought out by Calcomp. Joe