1. Whether the wiring is normal

Suggestion: the card reader should have 4 groups of key wires, such as  +12v, GND, d0 (wg0), D1 (WG1).

2. Whether the power supply is normal

Suggestion: the access card reader is usually of DC12V working voltage. The red wire is connected to 12V and the black wire is connected to GND.

3. Whether the reader properties are correct

Suggestion: the card readers are ID card, IC card, HID card, CPU card, encryption card reader, etc. Please confirm whether the card reader is compatible with the card before purchasing. If not, the normal card reading will be affected.

4. Wiegand output format incompatible

Suggestion: the access card reader uses Wiegand communication mode. And Wiegand is divided into wiegand26, wiegand34, wiegand66, etc., which are different in the length of output card number bytes. When using, please set the Wiegand format according to one standard to avoid inconsistent Wiegand data byte length between devices.

5. Abnormal data transmission caused by long line

Suggestion: generally, the effective length of Wiegand communication is 0 - 80m. At the same time, the wire material used in the line should be considered. If the line is too long, it is easy to cause incomplete data transmission (For example, the card number is 12345678 when reading the card once. And another number appears when reading the card again, which is the loss in the middle of transmission.)