rs232 - ttl converter

hi everyone,

i am using rs232 - ttl converter to communicate between my arduino uno and integrated RFID reader. both rfid and converter are DCE devices. i thing that is why my reader does not respond to ttl converter and arduino. is there any way to make connection b/w rfid reader and rs232 - ttl converter (max3232 ic).

thanks : :slight_smile:

Are you sure the rfid reader is actually RS232 voltage levels, not TTL serial?

It is extremely common to find TTL serial described as RS232, even in product documentation :-/

What model is the RFID reader? Have you checked to make sure the rx and tx lines are connected properly? Does the RFID reader use xon/xoff or any other handshake protocol?

Just to verify the arduino/rs232 adapter connections, try connecting the rs232 tx to rx on the adapter and see if the arduino can receive back what it is sending. (Note this may not work if you are using software serial).

Note also that if you attached the TX line of the RS232 side of an RS232<->TTL converter to the RX pin of a device that actually wanted TTL serial voltage levels, you have probably trashed the unfortunate device.