The OKY3505-2 is an RS232/TTL serial communication module manufactured by OKYSTAR. It is a serial converter that is designed to convert RS232 inputs to TTL outputs with a voltage range between 3-5.5VDC. The module features two UART transmitters and receivers, a GPIO port, a 3-pin VCC, and 5 GPIO pins for configuring and controlling the module. It is used in a variety of embedded applications such as microcontrollers, development boards, and other applications requiring a serial interface. It allows the user to easily communicate with their system and also supports multiple protocols such as RS232, RS485, and Ethernet. The OKY3505-2 is compact and lightweight, making it easy to integrate into existing systems.