What is the meaning of Half Duplex and Full Duplex?
Full duplex enables a switch port to both transmit and receive messages simultaneously, over two dedicated communication channels. Half duplex, by contrast, permits a port to transmit or receive messages in only one direction at a time. Signal collisions are possible in half duplex communications—because messages are transmitted and received over a single channel. Half duplex communications can cause poor performance and message loss.
What do you mean by Auto-Negotiation in network switches?
Auto-negotiation permits a switch port—connected to a remote device that also supports auto-negotiation—to automatically configure itself for the maximum speed and duplex configuration supported by both devices. However, it may be necessary to manually configure the speed and duplex settings of the switch port, if its peer device does not possess auto-negotiation capability.
What is Differential mode of signal transmission and how it is configured?
Differential mode is the normal way of transmitting electric and electronic signals. The Transparent Factory data in electric form are transmitted in differential mode. The current is propagated on one conductor and returned on the other conductor. The differential voltage is measured between the conductors.
When the one way and return conductors are side by side as in Transparent Factory cables and far away from disturbing currents, the differential mode disturbance is usually not significant.
What do you mean by Common Mode signal transmission?
Common mode is an interference mode where the current is propagated in the same direction on all the conductors and returns via the mechanical ground.
A mechanical ground (a conducting frame for instance), serves as a potential reference for the electronics and as a return for common mode currents. Any current, even a strong one, coming in one cable, in common mode into a unit which is insulated from the ground connections, comes out through the other cables, including Transparent Factory cables when they exist.
Why current flows in the earth cables? What are major sources?
An earth network carries leakage current and fault current from equipment, common mode current from external cables (electricity and telecoms mainly) and direct lightning currents into the earth. Physically, weak resistance (relative to a distant earth), does not concern us as much as the local equipotentiality of the building. In fact the most sensitive lines are those that connect equipment’s together. In order to restrict the circulation of common mode currents on cables which do not leave the building, it is necessary to restrict the voltage between interconnected equipment’s within the site. A mechanical ground is any hardware conducting part which is exposed, which is not normally live, but which could be in case of a failure.
How ground cables are connected in a cabinet?
Linking of ground connections inside a cabinet or a small machine is an essential parameter, because these ground connections are directly accessible for the electronic components.
When the ground connections are not linked properly, a cable with a common mode current disturbs all the others (including Transparent Ready electric cables). Proper interlinking of ground connections reduces the risk of this problem.
All the metal structures of the bay will thus be interconnected. The equipotential connections for safety must be supplemented by direct connections between all the elements of the machine or cabinet. Good methods for wiring the ground connections and for interlinking these connections should be applied to cabinets, machines and buildings.
