A Keystone Jack is a modular connector used in data communications. It is designed to snap into a wall plate or patch panel, providing a convenient and secure way to connect network cables. Keystone Jacks are available in various types, including RJ45 for Ethernet, RJ11 for telephone, and fiber optic connectors. They typically have a standardized 8-position, 8-contact (8P8C) interface, which provides a reliable and easy-to-use connection for networking equipment. Overall, Keystone Jacks are an essential component of modern data communications infrastructure.