We can see that middle and high-end data cables usually consist of several parts: rubber shell – braided mesh – aluminum foil – copper core. The inner layer of conductor core (copper core) wrapped by colored insulator is used for transmitting data signals and current, while the outer layer of rubber shell is used to protect the wire; And what is the role of the braided mesh and aluminum foil layers in the middle?

An important role of data cables is to transmit data signals. However, when we are using it, there may be all kinds of messy and interfering information around it. If these interfering signals enter the inner conductor of the cable and are superimposed on the originally transmitted signal, is it not possible to interfere with or change the originally transmitted signal, resulting in loss of useful signals or problems?

These braided mesh and aluminum foil layers play a protective and shielding role for the information we want to transmit. Of course not all data cables have two layers of shielding, some have more than one shielding layer, some have only one layer or even none. Shielding is the metallic separation between two regions of space to control the induction and radiation of electric and magnetic fields and electromagnetic waves from one region to another. Specifically, a shield surrounds the conductor cores to prevent them from being affected by external electromagnetic fields/interfering signals, and also prevents the interfering electromagnetic fields/signals within the wire from spreading outward.

The shield of the data cable is mainly made of copper, aluminum and other non-magnetic materials, usually braided copper mesh (aluminum-magnesium braided mesh) or copper berth (aluminum berth, etc.), their thickness is very thin, much less than the skin depth of the metal material on the frequency of use. One point to note is that one end of it must be connected to the signal ground of the circuit, because the effect of the shielding layer is not mainly due to the metal body itself on the electric field, magnetic field reflection, absorption, but due to the shielding layer of the grounding of the resulting, grounded in a different form will have a direct impact on the shielding effect.

Ordinary shielding wire production process is as follows:

Stranded copper — Extrusion (inner core) — Winding (inner core wire) — Covered aluminum — Braiding (or winding) –Extruded (outer cover) – Packed in rolls.

In electronic connecting wires, we often use letters to identify and introduce the materials used, such as:

AL stands for Aluminum Pool, e.g.: 4C+AL, which means a 4-core wire wrapped with Aluminum Pool.

AB stands for braided, such as: 4C + 80/0.10AB, meaning 4-core braided wire, braided specifications for the 80 0.10mm OD copper wire.

S stands for twisted, such as: 4C+60/0.10S, meaning 4C twisted wire, twisted specifications for 60 0.10mm OD copper wire.