an analog to digital converter 42 lamp voltage is also supplied to the converter current leaving the controller module via the switched power relay 30 is monitored by a current sensor 44 that supplies a current measurement signal to converter 42 and the voltage from switched power relay 30 is supplied as a voltage signal to the converter the lon chip 32 is a device that provides certain functions at each pole it turns the pole 39 s lamp s on and off by operating the lamp relay 28 in accordance with commands received by module 27 via the incoming power lines 14 it turns power to the next pole in the string on and off by operating the switched power relay 30 in accordance with commands received by module 27 via the incoming power lines 14 the lon chip 32 also provides data back to the control room 18 via the power lines 22 and lighting cabinets 16 this data includes lamp current lamp voltage and signals for indicating that a new ballast a new capacitor or new lamps have been installed communication between the lon chip 32 and power lines 14 is via interface 38 at the central control station the usage of each lamp is logged so that a running count of hours on is maintained voltages and currents are also logged any unusual event that causes an alarm to be given is also logged fig7 is a chart describing various functions performed by a controller module 27 in a lamp pole 10.