Radiografica Costarricense, the Costa Rican government data-communications agency, is boosting its national fiber-optic infrastructure by using the Sunrise, FL-based Racal Data Group`s PremNet 5000 backbone multiplexers. The multiplexers help transmit voice and data at 100 Mbits/sec. The current network comprises two rings of PremNet 5000 systems, and another five devices are scheduled for installation, to place an additional 150-Mbit/sec ring into service.