Abstract: A communication system for communicating between the master station and one or more groups of field stations wherein each group of field stations are interconnected with the master station by a full duplex communication link. Information originates at the master station and may be transmitted to a designated field station. The field station also originates data which is transmitted to the master station on request. The master station includes a digital computer to manage the system. Each remote station may have an individualized communication cycle period which dictates the maximum and minimum times between communication. The master station apparatus schedules communications, monitors communication attempts, controls retrys and logs the number of failures as well as the type of communication failure. The digital computer, running under program control directly controls an office modem controller which communicates, through a modem, with a selected field station modem, over the communication link.