Patent ID: 8123306

Claim:
A truck comprising: a pressurized air supply system for providing air to one of a plurality of air supply connections; and a selector circuit for providing selection to one of the air supply connections, wherein the circuit further comprises: a first inversion valve having a supply line connected to a selector valve and a control line connected to a parking brake valve; a second inversion valve having a supply line connected to the parking brake valve and a delivery line connected to a first one of the air supply connections; a synchro valve having a supply line connected to the parking brake valve and a delivery line connected to a second one of the air supply connections; a double check valve with supply lines connected to a delivery line of each of the first inversion valve and the synchro valve and a delivery line connected to a control line of each of the second inversion valve and the synchro valve; a first trailer supply connection to the delivery line of the second inversion valve; and a second trailer supply connection to the delivery line of the synchro valve.