RFID 125KHZ reader

Hi

Can i ask something ?

I got a Card-Reader Module (Mini 125khz RFID Module- External) - SKU113990043

so I wanna get a manual and some document of the Protocol about this model.

pls send me them.

and I have some problem when I was testing this model.

  1. There was no problem receiving data using the Arduino.

but I almost received a data that only “Null” when I was testing without the Arduino.

and then I could receive the right data once in a while.

What is the problem? any diffrence?

  1. If I compile SeeedRFID.H Codes on Arduino(included a Photo),

how does it affect to RFID Module ?

I didn’t understand this codes so pls explain the impacts of the RFID Module.