Abstract: The systems consists of an intrinsic collaboration among a message concentrator unit, a center operating unit, several visual displays, printers, information storage devices including operating and management software, insuring that modular telephones and both validation and identification units and access units control together with regional billing centers and a validation and billing center, as well as terminals of collecting entities by interchanging diverse specific operating messages within the public modular telephone management system-the whole context and operation arisen from their performance.