This software package was developed for automating of technological processes in communication's branches and hotels connected to automatic long-distance telephone station quasi-electronic system type "Quartz" of UkrTelecom, Ukraine, Zhitomir (some modified version, TLT-H, has been deployed to Kazakhstan, Karaganda), and was written in C and Assembler programming languages.
This application was successfully running 24x7 starting from 1992 till 2001 (at least as far I know, but may be later).
Conversion from original cp866 encoding (Russian) to utf-8 has been executed as below (except binary files):
for f in ./*; do iconv --from-code cp866 --to-code utf-8 $f -o $f.new && mv $f.new $f; done