The Intellisystem IT-232P33-TTL is a bi-directional port powered RS-232 to 3.3V TTL converter in a 9 pin format. It can convert any standard full duplex RS-232C port to a 3.3V TTL signal and vice versa. The unit is powered from the RS-232 data lines. It also supports data direction auto-turnaround. Therefore, no external power or flow control is required. The data direction auto-turnaround automatically enables the TTL driver when data is present on the RS-232 side making the device plug-and-play, requiring no software drivers. The IT-232P33-TTL has a DB9 female connector on the RS-232 side and either a DB9 male connector or 5-way terminal block on the TTL side. Separate terminal block is included in package.