The BT Redcare network is normally used for the security monitoring of domestic and business premises through the BT phone network. BT wished to develop the potential of their highly secure nationwide data network further and contracted NHDS to develop a power monitoring system that would be used by electricity distribution companies in the UK to monitor their HV (high voltage) feeders. Custom built monitoring units were installed in BT public phone kiosks which used the phone line to report to the electricity company control room, where a custom designed NHDS host system would receive, analyse and display the information. This system was initially designed for Yorkshire Electricity.