High density storage on a magnetic stripe card

A new variable rate code with soft-decision decoding has yielded a storage capacity of 2 kBytes (30 kbit/in/sup 2/) on a standard banking credit card. The capacity can be further increased through higher track density and using a computationally intensive Bayesian blind inverse filter. This work is continuing to an estimated 4 kByte (100 kbit/in/sup 2/) capacity while remaining compatible with current systems.