the 1970s and early 1980s (it was the cable used to connect IBM 3270 terminals to IBM 3274/3174 terminal cluster controllers). Later, some manufacturers of LAN equipment, such as Datapoint for ARCNET, adopted RG-62 as their coaxial cable standard. The cable has the lowest capacitance per unit-length when compared to other coaxial cables of similar size. All of the components of a coaxial system should have the same impedance to avoid internal reflections at connections between components (see Impedance matching). Such reflections may cause signal attenuation. They introduce standing waves, which increase losses and can even result in cable dielectric breakdown with high-power transmission. In analog video or TV systems, reflections cause ghosting in the image; multiple reflections may cause the original signal to be followed by more than one echo. If a coaxial cable is open (not connected at the end), the termination has nearly infinite resistance, which causes reflections. If the coaxial cable is short-circuited, the termination resistance is nearly zero, which causes reflections with the opposite polarity. Reflections will be nearly eliminated if the coaxial cable is terminated in a pure resistance equal to its impedance. Coaxial characteristic impedance derivation Taking the characteristic impedance at high frequencies, One should also know the inductance and capacitance of the two concentric cylindrical conductors which is the coaxial cable. By definition and getting the electric field by the formula of electric field of an infinite line, where is charge, is the permittivity of free space, is the radial distance and is the unit vector in the direction away from the axis. The voltage, V, is where is the inner diameter of the outer conductor and is the diameter of the inner conductor. The capacitance can then be solved by substitution, and the inductance is taken from Ampere's Law for two concentric conductors (coaxial wire) and with the definition of inductance, and where is magnetic induction, is the permeability of free space, is the magnetic flux and is the differential surface. Taking the inductance per meter, , Substituting the derived capacitance and inductance, and generalizing them to the case where a dielectric of permeability and permittivity is used in between the inner and outer conductors, Issues Signal leakage Signal leakage is the passage of electromagnetic fields through the shield of a cable and occurs in both directions. Ingress is the passage of an outside signal into the cable and can result