The SP3232EB is a clone of the MAX3232 RS232 converter IC capable of running at 3V and communicating with 5V logic.
This board takes the SOIC packaged SP3232EBCA and breaks out all the pins that you need to set up your RS232-to-TTL connection. It also includes the necessary 0.1uF charge-pump capacitors. Because the SP3232EB operates at a voltage range of 3V to 5.5V, you can use this on both your 3.3V and 5V projects.
Board pinout: T1OUT, T2OUT, R1IN, R2IN, 3V-5.5V, GND, T1IN, T2IN, R1OUT, R2OUT.
RS232-to-TTL Board Resources