I am an I/O expansion module based on I2C interface control, which can expand up to 16 I/O ports and support the simultaneous use of up to 8 expansion modules, providing up to 128 I/O ports. Compatible with 3.3V and 5V levels, the I2C interface requires only 2 signal lines to expand 16 I/O ports. The I2C communication address is configurable by shorting A0/A1/A2 solder joints. Offers two interface types: PH2.0 terminal and solder pad, supporting parallel connection of multiple I2C modules. Onboard level conversion circuit ensures compatibility with 3.3V and 5V operating levels. Working voltage: 5V or 3.3V Control interface: I2C Product size: 38mm x 23mm Via diameter: 2.0mm Color: As shown Material: PC Note: Due to different product batches, appearance may vary slightly but does not affect functionality. Package contents: 1 x Expansion module, 1 x Cable Light reflection and display differences may cause slight color variations between the image and actual item. Measurement error allowance: +/- 1-3cm.