Many Windows users come across the SD card reader not working error after the Windows 10 update and fail to get access to their important SD card data. It's a very nerve-wracking but also common issue that Windows 10 is stuck on the “SD card not recognized” problem. Don’t be worried. In this Windows 10 guide, we’ll walk you through top 4 ways to tackle this card reader not working issue.
In the 26-bit Wiegand format, bit 1 is an even parity bit. Bits 2–9 are a facility code. Bits 10–25 are the card number. Bit 26 is an odd parity bit. 1/8/16/1. Other formats have a similar structure of a leading facility code followed by the card number and including parity bits for error checking, such as the 1/12/12/1 format used by some American access control companies.
A reader radiates a 1" to 20" electrical field around itself. Cards use a simple LC circuit. When a card is presented to the reader, the reader's electrical field excites a coil in the card. The coil charges a capacitor and in turn powers an integrated circuit. The integrated circuit outputs the card number to the coil, which transmits it to the reader.