I’m trying to hook up Arduino with a serial<->wifi port, the Lantronix Wiport (www.lantronix.com/device-networking/embedded-device-servers/wiport.html) , my original thought was to use the TWI on arduino (The TX/RX pin, or Pin 0 & 1) to interface with the serial port on the Wiport. According to the spec the Wiport supports a 3.3v CMOS level serial.
So here’s the problem, there’s a TXD and RXD pins on the board, and it tolerates up to 5V. So I just give it a try and connect the TX pin from Arduino to the RXD pin of the Wiport, and the same for the RX pin. I’m sure the baud rate is right, but nothing happens, any idea? Would a simple level shifter do the job? Or I’m just mismatching the concepts for all these RS232/CMOS/5/3.3V/TWI/TTL?