which RFID module are you using? send the picture of your module or schematic. if you dont have max232 on the rfid board then you may need one circuit for that and a max 232 at the controllerend too. what interface does your rfid module use? first connect rfid module to serial port of pc and in hyperterminal after setting the terminal setting properly swipe the rfid card and see if you see any output printed on the terminal.
If D0 and D1 are giving TTL o/ps then why do you have to connect it to MAX232? Can't you connect it directly to mcu? What are the pin specifications of D0 and D1?
For Example If The card Shown Above is Placed on the Reader ,
UART Data Will be 159 48659
Parity |---8BIT--|-------16BIT---------------|Parity
Wigend O/p Will be 1 1001 1111 1011 1110 0001 0011 0
check this link...my rfid diagram is available here.
**broken link removed**
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yes it correct..i can connect directly to mcu. The pin D0,D1 will give the wiegend protocol output. where low signal send through D0 and high signal will send through D1.