Copper is the most common form of cabling for networking. It's rated highly for conductivity and as such can conduct electricity more easily than other metals.
It's much cheaper than fiber, however, it's much slower in terms of data rates. If speed is of the essence, fiber is better for the same thickness of cable.
Being metal, interference can be an issue. Radio bursts and electromagnetic noise can degrade signal quality to the point of being unusable depending on the environment, and there's also the potential for wiretapping, unlike fiber.
Being an older standard, copper has the benefit of excellent interoperability and legacy compatibility. There are two types of copper cabling that should be used for electrical timing signals (IRIG-B, DCF-77, Custom Pulses).
Coaxial cable or Coax is a type of copper cable that offers superior performance over other copper wiring options. Coax has 4 main components to its cable.
1. The core. This is made of copper or another conductive material. This is responsible for passing through data as an electrical signal.
2. The next layer is a dielectric insulation layer - this is usually plastic.
3. The third layer is the shield, also made of copper. The shield is usually a combination of electrical tape and braided mesh wrapped around the dielectric, and is used to help absorb any external interference that may affect the transmitting of data.
4. The fourth layer is a plastic coating which protects the internal layers from damage.
The dielectric provides distance and insulation between the inner conductor and the outer shield, the next layers above are collectively referred to as the shield. The different layers of the cable are shown below.
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Coax is often used with antennas or transmission lines in cases where fiber is too expensive or overrated. Different coaxial cables have different levels of protective shielding from electromagnetic interference (EMI), and varying amounts of loss through their dielectric. In general, coaxial cables offer a much higher transmission capacity than twisted pair cabling, and better EMI shielding, but are more expensive, and are harder to install as they often require the use of adapters.
Shielded Twisted Pair
Shielded twisted pair (STP) cabling consists of wire pairs twisted around each other to reduce crosstalk.
The wires in the pairs are insulated with color-coded plastic, and the pairs collectively are wrapped in foil to reduce EMI. Similar to Coax, around the foil-covered wire pairs is a braided copper mesh to reduce EMI, which is surrounded by the plastic wire insulation. An image of this is shown below.
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STP cabling is more susceptible to crosstalk than Coax, has lower transmission rates, and is less durable, but it is easier to install as its wires can be easily broken out, and it is cheaper. We would recommend this cabling option for timing signals if there is no requirement for the advantages offered by Coax.