Abstract: A tri-state electronic vehicle system control circuit comprises a plurality of 3-position switches, each of which is coupled to a dedicated pin on a wiring harness for coupling multiple portions of a combination vehicle such as a tractor-trailer combination. Each switch controls a device (e.g., brake lights, turn signal, etc.) and a data link that can be selectively toggled in a manner that permits data transmission without perceptibly affecting device function. Alternatively, two devices controlled by a given switch can be enabled by a single pin on the wiring harness. The tri-state switching circuitry thus doubles the capacity of the wiring harness to which it is applied.

Abstract: A tri-state electronic vehicle system control circuit comprises a plurality of 3-position switches, each of which is coupled to a dedicated pin on a wiring harness for coupling multiple portions of a combination vehicle such as a tractor-trailer combination. Each switch controls a device (e.g., brake lights, turn signal, etc.) and a data link that can be selectively toggled in a manner that permits data transmission without perceptibly affecting device function. Alternatively, two devices controlled by a given switch can be enabled by a single pin on the wiring harness. The tri-state switching circuitry thus doubles the capacity of the wiring harness to which it is applied.

Abstract: A valve member for use in a medical manifold valve assembly, wherein the valve member comprises a valve stem having a handle formed thereon for rotating the valve stem within the bore of a manifold. The valve stem has at least one pathway therethrough that can be aligned with channels through the manifold to allow fluid to flow through the valve stem pathway. The valve stem comprises at least two grooves circumscribing the valve stem, one groove above and one groove below each pathway opening. These grooves are preferably fitted or molded with a flexible material to form seals. The diameter of the valve stem above and below the area between the grooves is less than the diameter of the valve stem between the grooves such that the valve stem wall above and below the area between the grooves does not contact the bore wall.