Encoding & Access
Card format
The data structure encoded on an access card, such as 26-bit H10301 or 37-bit H10304.
The format defines how the facility code and card number are arranged. Your access system expects a specific format.
The format is the blueprint for how a card's facility code and ID number are packed into bits, 26-bit H10301 is the common open format, but many sites use proprietary or higher-bit formats. Your access system expects one specific format; mismatches simply do not read.
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