They are directly linked via GalNet to the bank-account and can only be activated / used when several biometric conditions are met. Including brainwave patterns which have shown to be unique to all Union beings including non-carbonbased lifeforms.
Transactions are done either via verbal command or the intuitive entering of ammounts manually. A credit strip only needs to touch another credit strip or paypoint to complete the transaction.
Credit Boxes are similar but do not need a GalNet connection as they have preloaded fixed Credit ammounts and can be used by anyone and are the equivalent of cash.
Credit Cards also exist but are different from Credit-Strips and a line of credit can be accessed usually via a third party provider such as SII-Freedom, Galactic Visa, Universal-Master or Union Express.