Presented in this paper is a new multiplex communications technology that economically permits a two-way transfer of information (data) between a tractor and trailer(s) through the standard SAE J560 connector. Power Interval Communications Technology (PICT) is a single wire, serial communication system that is transmitted over the existing turn signal circuit.This paper will show the basic approach of the PICT system and the major advantages it offers. PICT allows the use of the current SAE J560 connector to provide an in-cab trailer ABS fault indication. PICT, transmitted over the turn circuit, is compatible with all tractor and trailers, old and new, because this circuit is common to all vehicles. PICT is a very economical solution because no twisted pair communications wiring is required, no in-line switched communications techniques are required, no sophisticated interface circuitry is required, and no additional connections are required between the tractor and trailer. The PICT system utilizes the standard SAE J560 connector, existing tractor and trailer wiring, and electronic modules that communicate with one another via the turn signal circuit.The PICT communication system also has the capability of achieving productivity and safety increases for tractor/trailer owners. PICT's 2-way communication allows additional features in the trailer such as door ajar. tire pressure, brake pressure. reefer temperature, dome lamp control and another power switching function, plus a number of other functions that can be controlled and monitored in the cab.