Access badge

Entry points may be doors, turnstiles, parking gates or other barriers.

The most common technologies are magnetic stripe, proximity, barcode, smart cards and various biometric devices.

The transaction is stored in the system for later retrieval; reports can be generated showing the date/time the card was used to enter the controlled access point.

The new technologies retained the Wiegand upstream data so that the new readers were compatible with old systems.

The integrated circuit outputs the card number to the coil which transmits it to the reader.

To counteract this problem some manufacturers have created formats beyond 26 bit Wiegand that they control and issue to an organization.

Other formats have a similar structure of leading facility code followed by card number and including parity bits for error checking.