Receiver,transitter, rfid module conection to uc

[geethucmohan1992]

I am doing a project on RFID based shopping cart...but now am having a few problems. I am having trouble connecting RFID module to the microcontroller(AT89S52) am using.
The RFID module i purchased consists of EM-18 reader module and it has been connected to max232 and then to RS-232...so the module has rs232 output..now can i connect directly from rs232 to tx pin of microcontroller? or is there another way?
the following site says use max 232 and then to uc. but i have rs232 output..so how to?

**broken link removed**
i have attached the picture of my rfid module

Also, I have a transmitter for which am using MO-SAWR-ASK transmitter. That is to be connected to my microntroller (AT89S51). Is it ok to connect its data pin directly to the Tx pin of uc?

And the receiver OX-RX02-ASK recieves the data and this is to be connected to a second microntroller. Can i directly connect its data pin to Rx pin?

I also have to recieve the same to a PC or laptop. Now a days laptops dont have RS232 port, so how to receive the same in pc? can i use a 3rd uc, so that receiver is connected to uc, then to max232 then rs232, but then how to connect from rs232 to pc/laptop?

 

[Nigel Goodwin]

You can buy (quite cheaply) USB/RS232 converters - simply use one of those between PC and your RS232.

Directly connecting the modules to the uC pins depends both on the voltages and polarities involved - if you check my PIC tutorials there's an example in the RF tutorial.

 

[MikeMl]

You don't hook the RFID reader to the TX (transmit) pin, you hook it to the RX (receive) pin. Also, if it is truly RS232, then you need a MAX 232 to convert it back to logic levels before going into the RX pin.