Wired Communication Systems

Wired communication systems include all communications systems for which data is sent through a wire.

Types of Wired Connections

Twisted pair: Consists of a pair of wires that are twisted together. The twisting reduces noise on the wires by cancelling out, to a certain extent, the amount of electromagnetic interference from the environment and between transmit and receive

Coaxial Cable: Coaxial cables consist of a cylindrical wire running down the middle of an insulating sheath. Surrounding the insulating sheath is a conductive sheath, acting simultaneously as a shield and a return path for the signal. Coax cables are highly resistant to noise due to the shielding which keeps most of the EM energy inside the surrounding conductive sheath.

Fiber Optic Cable: A fiber optic cable consists of a very long thin fiber of glass down which light pulses can be sent. The data rates supported by fiber optic networks are incredibly fast.  So fast in fact that most people involved in fiber optic development now say that in relation to network speeds, computers are hopelessly slow, and so we must try to avoid computation at all costs.

Advantages (versus Wireless Communication)

• higher immunity to outside interference and noise
• Allocation of frequencies is determined by the owner(s) of the wire, not by regulatory authorities

Wireless Communication Systems

Wireless communications systems are, of course, communications systems that do not use wires. This category could include such anachronisms as smoke signaling and semaphores, but on this site, we are going to study only wireless electromagnetic communications which includes RF, microwave, and light.

Advantages (vs. wired communication)

• cheaper to deploy, especially if the network covers a large area with no current coverage. There is no need to connect wires to all the points that need coverage.
• Usually easier to deploy, but that depends a bit on the size of the network. A point to point connection might be easier to wire.
• Users of the network are more mobile; they are not tied down to any particular spot.