Stackable networking device and method having a switch control circuit

DETAILED DESCRIPTION It is an object of the present invention to provide a dual-speed stackable networking device capable of preventing a traffic loop by implementing a switch control circuit in the stackable networking device.
It is another object of the invention to provide a cost-effective dual-speed stackable networking device which can save the cost of CPU by implementing a simple switch control circuit for controlling the operations of the exchanging unit.
A first stack bus connects with all the first signal repeaters of every dual-speed stackable networking device, to exchange data between the first repeater of every dual-speed stackable working device.
A second stack bus connects with all of the second repeaters of every dual-speed stackable net working device, to exchange data among the second repeaters of each dual-speed stackable networking device.
One switch control circuit is added to each dual-speed stackable networking device, which includes some switch control circuits connected to the same switch control circuit of the other dual-speed stackable networking device.
These circuit units switch control circuit have an output end for sending a high or low voltage signal to the next circuit unit of the other switch control circuit.
It has an input end for receiving a high or low voltage signal from the other switch control circuit and a detector connected with the exchanging unit.
The switch control circuit generates a high voltage signal when the exchange switch is on.
A logic unit is connected with the input end, and the detector and exchanging unit.
When the signal from the input end is low and the signal from the exchanging unit is high, the logic unit generates a high volume signal to the output end and makes the next exchanging unit on.
It generates a low voltage signal to the next exchanging unit and turns the next exchanging unit off, when the signal from the input end is high.
The repeaters of the above-mentioned design are typically either of transfer speed of 10 Mbps or 100 Mbps