As a message handling system installed in the public communication networks, SSC (Store and Processing Service Control Facility) provides convenient communication processing services using storage and conversion technologies. The SSC conversion facilities, including media conversion from teletex codes to facsimile image, increase the communicable terminal range. Mailbox services, using four different kinds of personal Message Boxes in the SSC, bring about much benefit to personal communications. The SSC service requesting procedures facilitate multi-address delivery, timed delivery and automatic conversions. The SSC is a prototype which realizes the Message Handling Systems being studied in CCITT. The system is under developmental research in the NTT Laboratory.