5V TTL to 3.3V serial connection

Hi Everybody !
I need to make a serial conexion between a sensor and a RCM4200 module, the first one works in 5V TTL and second has 3,3 Volt in its serial port. It is posible do a direct connection?, or a I need a aditional component at the middle of these two devices (sensor and RCM4200) ?
Thanks in advance.

Sebastián Acosta
Electronic Engineer