【My Study Note】Cables
Cables
Cables are what connect different devices to each other, allowing data to be transmitted over them.
Two categories of cables
Copper Cables
Copper cables are the most common form of networking cable. They’re made up of multiple pairs of copper wires inside a plastic insulator. The sending device communicates binary data across these copper wires by changing the voltage between two ranges.
The system at the receiving end is able to interpret these voltage changes as binary ones and zeros, which can then be translated into different forms of data.
Common Copper Twisted Pair Cables in Networking
These are all shorthand ways of saying category 5 or category 6 cables. These categories have different physical characteristics, like the number of twists in the pair of copper wires that results in different usable lengths and transfer rates.
However, from the outside, they all look about the same, and even internally, they’re very similar to the naked eye. The important thing to know is that differences in how the twisted pairs are arranged inside these cables can drastically alter how quickly data can be sent across them and how resistant these signals are to outside interference.
Cat 5 cable
Cat 5 is older and has been mostly replaced by Cat 5e and Cat 6 cables.
Cat 5e cable
Cat 5e cables have mostly replaced those older Cat 5 cables because their internals reduces crosstalk. The receiving end isn’t able to understand the data causing a network error. Higher-level protocols have methods for detecting missing data and asking for the data a second time, but of course, this takes up more time.
The higher quality specifications of a Cat 5e cable make it less likely that data needs to be retransmitted. That means on average, you can expect more data to be transferred in the same amount of time.
What’s Crosstalk?
Crosstalk is when an electrical pulse on one wire is accidentally detected on another wire.
Cat 6 cables
Cat 6 cables, follow even more strict specifications to avoid crosstalk, making those cables more expensive. Cat 6 cables can transfer data faster and more reliably than Cat 5e cables can, but because of their internal arrangement, they have a shorter maximum distance when used at higher speeds.
Fiber Cables
Fiber cables contain individual optical fibers, tiny tubes made out of glass about the width of a human hair.
These tubes of glass can transport beams of light. Unlike copper, which uses electrical voltages, fiber cables use light pulses to represent the ones and zeros of the underlying data.
Fiber is even sometimes used specifically in environments where there’s a lot of electromagnetic interference from outside sources because this can impact data being sent across copper wires. Fiber cables can generally transport data quicker than copper cables can, but they’re much more expensive and fragile.
Fiber can also transport data over much longer distances than copper can without suffering potential data loss.