Interface-I/O expanders are electronic devices that enable the expansion of input and output (I/O) capabilities in various systems. They allow users to add more inputs or outputs to their system than what is originally available, providing greater flexibility and functionality. These expanders can be used in various applications such as industrial automation, medical equipment, and audio/video systems. They come in different types such as serial, parallel, and networked expanders, each with its own set of features and benefits. With interface-I/O expanders, users can easily scale up their systems without having to upgrade the entire infrastructure, making them a cost-effective solution for a wide range of industries.