The document is a user manual for the KYL-812 wireless ON-OFF input and output module made by Shenzhen KYL Communication Equipment Co., Ltd. It summarizes the module's functions, features, and connection definitions. The module allows for wireless transmission of 4 input channels and 4 output relay channels between a transmitting and receiving device located within 2-3 km of each other. The DIP switches are used to configure settings like the working mode, channels, and transmission interval.