As we all know, in every communication system, all the sending and receiving devices, like fiber optic switch, need to adopt massive bundles of wires or cables to achieve connections for data transfer. Nowadays, the most common cable types used in communication systems are twisted pair cable, coaxial cable and fiber optic cable. With these three cable types equally deployed in network communication, people may feel confused which one is the ideal choice for their networks? This article aims to introduce some differences among twisted pair cable, coaxial cable and fiber optic cable and to tell you how to distinct them from each other in terms of features and specifications as well.
Twisted pair cable is a type of ordinary wiring which connects home and many business computers to the telephone company. It is made by putting two separate insulated wires together in a twisted pattern and running them parallel to each other which helps to reduce crosstalk or electromagnetic induction between pairs of wires. Twisted pair cable is good for transferring balanced differential signals. The practice of transmitting signals differentially dates back to the early days of telegraph and radio. The advantages of improved signal-to-noise ratio, crosstalk, and ground bounce that balanced signal transmission brings are particularly valuable in wide bandwidth and high fidelity systems.
According to whether the cable has a shielding layer, there are two common types of twisted pair cables—shielded twisted pair (STP) cable and unshielded twisted pair (UTP) cable. STP cable is available for Token Ring networks, while the UTP cable is more suitable for Ethernet networks. The most common UTP cable types applied in Ethernet network are cat5e, cat6a and cat7 cables, etc. The following image shows the different structure of UTP and STP cables.
Pros: Twisted pair cable is more flexible and cheaper than coaxial cable and fiber optic cable, and it is easy to install and operate.
Cons: It encounters attenuation problem and offers relatively low bandwidth. Besides, it is susceptible to interference and noises.
Like twisted pair cable, coaxial cable or coax cable is another type of copper cable which has an inner conductor surrounded by a foam insulation, symmetrically wrapped by a woven braided metal shield, then covered by in a plastic jacket (as shown in the following image). This special design allows coaxial cable runs to be installed next to metal objects such as gutters without the power losses that occur in other types of transmission lines. Coaxial cable acts as a high-frequency transmission cable while contains a single solid-copper core, and compared to twisted pair cable, it has over 80 times the transmission capability. This kind of cable is mainly adopted in feedlines connecting radio transmitters and receivers with their antennas, computer network connections, digital audio (S/PDIF), and distributing cable television signals. 75 ohm coaxial cable and 50 ohm coaxial cable are two coaxial cable types. 75 ohm cable aims to transmit a video signal, while the 50 ohm cable is designed to transmit data signals in a two-way communication system.
Pros: Coaxial cable can be installed easily, relatively resistant to interference.
Cons: It is bulky and just ideal for short distance transmission.
Unlike twisted pair cable and coaxial cable with wires inside, fiber optic cable consists of a bundle of glass threads, each of which is capable of transmitting message modulated onto light waves. There exist various types of fiber optic cables, which are determined by the number of fibers and where it will be installed. Currently, two types of fiber optic cables are widely adopted in the field of data transfer—single-mode fiber optic cable and multimode fiber optic cable. A single-mode fiber optic cable has a small fiber core and only allows one mode of light to pave through at a time, so it is available for high-speed and long-haul applications. By contrast, a multimode fiber optic cable has a much bigger fiber core and it can carry multiple light rays at a time, so it is more ideal for short distance data transmission. The following table shows some differences between single-mode and multimode fiber optic cables.
Pros: Compared to the above mentioned copper cables, fiber optic cable takes more advantages, such as lighter, better performance and higher bandwidth. But the biggest advantage of fiber optic cable is that it can transmit much more data with the lowest loss at higher speed for longer distance.
Cons: Nevertheless, it needs complicated installing skills, and much more expensive than copper cables.
Whether to choose twisted pair cable, coaxial cable or fiber optic cable totally depends on the specific circumstances where you should take cost, performance and supporting transmission rate and length into consideration. Through this passage, hope you can figure out the differences between these three cable types.