Custer Telephone Co-op (CTCI) is a regional mobile network operator serving parts of the United States. Operating within the North America & Caribbean region, CTCI plays a vital role in providing cellular connectivity to communities, especially in areas where larger national carriers may not have extensive coverage. CTCI is identified by its Mobile Country Code (MCC) of 313, which designates the United States, and its Mobile Network Code (MNC) of 220. These codes are crucial for mobile devices to properly identify and connect to the CTCI network. While CTCI may not have the nationwide reach of larger providers like Verizon, AT&T, or T-Mobile, its localized focus allows it to cater specifically to the needs of its service area. This often includes providing essential communication services to rural populations and supporting local businesses. Its smaller size can provide benefits in responsiveness and community involvement often prioritizing rural connectivity in areas that other networks may overlook, ensuring a vital link between residents and the wider world. CTCI exemplifies how smaller, regional operators can contribute significantly to the overall telecommunications landscape.