FTC Message Switching Systems

Thrust into a highly competitive market place by deregulation, a leading international record carrier needed to upgrade its service capabilities with a series of sophisticated store-and-forward message switches for telex messages, cablegram services and private networks using low and high speed data links.

The Sombers Group built the company’s fault-tolerant Tandem Computer-based switching systems, which were installed both in the U.S. and overseas. The switches provided a full range of services, including receipt and delivery acknowledgement, sequence number control, message retrieval and recovery, automatic editing and reformatting, operator intercept positions, multiple and mnemonic addressing, automatic retry and alternate routing, quota routing and complete accounting.

A major feature of the switches was a proprietary Message Definition Language (MDL) that allowed the on-line definition of new message source and destination formats and error handling procedures. New customers with totally new requirements could be brought on-line without taking the system down to install program modifications.

The switches connected the various protocols of the outside world via Data Line Controllers (DLCs). These microprocessor-based DLCs were manufactured by The Sombers Group and converted most national and international Telex and TWX protocols to those supported by Tandem. A single Tandem communications port could support many low speed lines via the multi-dropped DLCs.