Racal Electronics Plc has expanded its US data communications operations with acquisition of the 70% of Anaheim, California fibre optic systems manufacturer Quanta Communications Systems Inc it did not already own, on undisclosed terms. Newly-named Racal-Quanta makes low- and high-speed fibre optic modems and multiplexers for asynchronous and synchronous applications, co axial-elimination multiplexers for use with IBM 3270s, and intelligent multi-interface fibre multiplexers.