Table of Contents
Learn the different types of problems you can encounter while working with cables.
EMI: External signals that interfere with the network. Common sources include generators, motors, elevators, transformers, and fluorescent lighting.
RFI: Same thing as EMI but with radio (I.E radio transmitters cause RFI the same way generators cause EMI)
Fixes:
Use fiber optic cables / shielded twisted pair cables
Don't install cables near EMI/RFI sources
Crosstalk: Interference caused by signals within twisted pairs
Fixes:
Twist wires into pairs at different rates
Increase twisting frequency of the wires
Attenuation: Loss of signal strength from one cable to another.
Longer cable = more attenuation
Higher temp cables experiecne more attenuation than lower temp ones
Use a repeater to regenerate the signal
Impedance: Measure of resistance within the transmission medium
Measured in ohms (Ω)
All cables must be at the same level of impedance
Choose the cables with the correct rating (50 or 75 usually) based on network type
signals are distorted when they pass through cables of differing impedance levels
Throughput: Rate that signals are processed and delivered over a communication channel
Each circuit module has a specified estimated throughput
Most modern wireless access points can run in 5g mode, 2.4g mode, or mixed mode.
Some access points support both standards, meaning one radio channel can run 2.4, while the other can run 5.
You can turn off the 2.4g antenna and use the extra antenna for your 5g clients and increase throughput using MIMO
MIMO is using two antennas as one, with one antenna handling transmission and one handle receiving information.
Cheap antenna + Cheap NIC = worse throughput
High-quality antenna + High-quality NIC = better throughput
Short: When electrical signals take a path other than intended
Usually caused by physical damage to wires causing them to touch or otherwise be able to transfer signals to eachother
Open Circuit: When a cut in a wire prevents the original signal from reaching the end of the wire
Miswired Cable: caused by incorrect wire positions that prevent the original wire from transmitting what was intended.
Using a crossover cable where you should be using a straight-through is one example
Wiremapping: matching a wire and a pin on one end with the same pin on the other end.
An error in wire mapping would be mapping the wire at pin 1 to pin 4, for example.
Split pair condition: is a single wire in two different pairs reversed at both ends.
For example, if instead of the solid green wire, the solid brown wire is matched with the green/white wire in pins 1 and 2.
Incorrect termination: When an incompatible or incorrect connector is used.
results in reduced preformance or connection loss
Bad connector: When a damaged connector causes connectivity issues
Most network devices have hot-swappable transceivers in order to allow for interfaces tailored to different cable types, protocols, and speeds.