Something or someone to which one resorts as an alternative to a failed resource or method.
A transaction that is verified by a method other than the optimum available on both the card and the device. In a maturing chip and PIN environment, fallback to signature, key entry or paper will be actively discouraged and will eventually disappear altogether.
When it's made available, a fallback is what's provided as a possibly acceptable compromise solution if a main function, eg in a PC or communication path, fails to work.
Fallback is something that happens on failure of call set up or on loss of channels. E.g. when an ISDN call is made the systems try to connect using BONDING, if this fails then fallback occurs so that the ISDN channels are set up using H.221 dialling.
(n.) A reversion to the environment that ran previously. Use fallback when you are activating an environment and the boot environment that is designated for booting fails or shows some undesirable behavior.
A reversion to the environment that ran previously. Use fallback if the updated boot environment fails to boot or shows some undesirable behavior.