These would emulate a number of terminals, translate the messages, codes and addresses, wrap them in SMARTs own communications protocol, and provide the interface over Datex to the various travel agencies.
The interfaces were similar to those for direct connections, but provided some standardization for codes to ease the transition between the systems.
The STE would also allow printing of documents, tickets, bills and similar, as well as interfacing with the accounting system.
It constantly monitored the status of all STEs and reported suspected errors in the STE hardware or communication lines.
Furthermore, it could remotely configure the STEs, download application software and/or operating system, and reboot the computers - all automatically without any intervention.