# FAQ

- What does Capacity "C" mean?
- Measured in Farad/length unit.

Expresses the capacity of a dielectric material, laid between two conductors, to retain the dielectric charge when there is a difference of potential between the two conductors. For data transmission it is advisable the use of low capacity cables to reach long distances. - What does Inductance mean?
- Expressed in Henry/length unit.

When two coaxial conductors are run by equal and opposite currents a magnetic field is created in the space between them.

The ratio between the flux that crosses the space between the two conductors and the current which produces it, is called inductance. The inductance is the primary constant of the cable and is influenced by the distance of the two conductors, the diameter of the conductors and by the relative magnetic permeability of the constituent materials. - What does Attenuation mean?
- Measured in db/length unit.

The attenuation determines the level of transmission of a line. It is also the ratio between the input voltage and the output one. The attenuation of a digital impulse is solved in a degradation and distortion of the signal, with a loss of the voltage peak and therefore in a slowing down of the impulse. - What does Propagation velocity mean?
- Propagation velocity or lag is the time required by signal to run through a transmission line. Expresses the ratio between the signal velocity in its means of transport (isolation) and the velocity of itself ether way in percentage. This value is essentially in function of the dielectric constant of the material of the isolation.
- What does Impedance mean?
- Expressed in Ohm.

The impedance value indicates the total opposition to the electron flow offered by a transmission line. In a transmission system of long distance or high frequency, it is very important that the Ohm value at the beginning is constant and continuous at the receiving. - What does Resistance "R" mean?
- Measured in ohm/length unit.

Expresses the resistance of materials to the electron flow when a strength is applied (voltage). The higher is the resistance, the lower is the signal transmitted. The resistance of the conductor is of primary importance for the determination of the transport capacity of the signal on the transmission line. The value "R" is given by the ratio between the resistivity of the material and its section.