Abstract: Disclosed are an implement descending stability control method and system and a tractor. An outlet of a main pump is communicated with an inlet of a main overflow valve, an inlet of a constant-difference overflow valve and an inlet of an implement control valve. An oil outlet of the implement control valve is connected with a spring cavity of the constant-difference overflow valve through a steady-state throttle valve and is communicated with an inlet of a switching valve. An oil outlet of the switching valve is connected with a rodless cavity of a suspension cylinder in a suspension mechanism, and the rodless cavity of the suspension cylinder is communicated with an inlet of a descending valve. A rod cavity of the suspension cylinder is connected with an inlet of a secondary overflow valve.

Abstract: Disclosed are an implement descending stability control method and system and a tractor. An outlet of a main pump is communicated with an inlet of a main overflow valve, an inlet of a constant-difference overflow valve and an inlet of an implement control valve. An oil outlet of the implement control valve is connected with a spring cavity of the constant-difference overflow valve through a steady-state throttle valve and is communicated with an inlet of a switching valve. An oil outlet of the switching valve is connected with a rodless cavity of a suspension cylinder in a suspension mechanism, and the rodless cavity of the suspension cylinder is communicated with an inlet of a descending valve. A rod cavity of the suspension cylinder is connected with an inlet of a secondary overflow valve.

Abstract: The present invention provides an IP telephone gatekeeper system and an implementation method thereof, characterized in that two or more individual gatekeepers are connected each other, so as to forming a gatekeeper system that can be regarded as a single gatekeeper system by the controlled gateways, in which the gatekeepers can substitute and backup mutually. A plurality of computer systems are used to realized the cooperation of a plurality of gatekeepers, for breaking through the limit of capacity of individual gatekeeper group and improving the reliability of the whole system, so that backing-up and substituting mutually can be achieved.

Abstract: The present invention provides an IP telephone gatekeeper system and an implementation method thereof, characterized in that two or more individual gatekeepers are connected each other, so as to forming a gatekeeper system that can be regarded as a single gatekeeper system by the controlled gateways, in which the gatekeepers can substitute and backup mutually. A plurality of computer systems are used to realized the cooperation of a plurality of gatekeepers, for breaking through the limit of capacity of individual gatekeeper group and improving the reliability of the whole system, so that backing-up and substituting mutually can be achieved.