Select 1. System Introduction 2. System Configuration 3. Characteristics and Merits of the System 4. System Specification 5. Example of System Operation 1. System Introduction The system is an optic distribution system for subway installation. The system is designed to reduce shaded or blanket areas and to provide quality service to subscribers in the main sections of subways, platforms, ticket booths, stairways, aisles and subway stores. The system can link itself to directly BTS and transmit BTS signal without undermining signal quality through fiber and coaxial lines. The system can deliver cost-effective underground services. It can transmit signals from three base stations through a single system by being linked with BTS in cellular bandwidth.