Functionality not tested but does power on and is recognized by the router. The Cisco NIM-4FXO is a 4-port voice interface NIM module designed to work with Cisco routers. It features both RJ-11 and RJ-45 connectors, providing compatibility for various networking setups. With its compact dimensions of 3.0 inches in height, 7.5 inches in length, and 2.3 inches in width, this module is easy to install and offers reliable voice interface functionality for enterprise networking environments. It is specifically designed for use with the Cisco NIM port and is a valuable addition to any networking setup requiring multiple voice ports.