Thank you amandu for suggestions
I have a customer, which wants to read just simple 125Khz cheap cards, to give access to setup of an industrial machine.
They used keys, but too many keys in the plant on everybody pocket.
They used keypad with password, but the password was even posted on Facebook by a guy
Now the want to distribute rfid key-fobs and keep a strict control of every person accessing the setup menu
The microchip controller, will read the rfid tag serial and send it through rs232 to the PLC. This one will permit or not setup and store the user id with date and time
Range is small, almost touch , 10 cm the most.
I do not need a high end
Just a module which have antenna incorporated and on TX output, preferably on 5VDC, and DIRTY CHEAP.