AVR-Chat

Hi

The query is about RFID , I have RFID tag ( Transponder) Clamshell as
125Khz ,so:

1.chip number U2270B or H4102 could comply with this kind of RFID tag ?
2.if yes, how can I connect this chip ( IC ) with micro controller AVR
? by UART ,maybe?
3.what is difference between ISO 14443 and Wiegand protocol?

appreciate your urgent help.....