Wireless Communications Basics ---- Bands (2.4 GHz and 5 GHz)

(1) Wireless communications media
Computers connect to routers via network cables for wired communications. They can also connect to the Wi-Fi for wireless communications. The medium of wired data transmission is network cables while that of wireless data transmission is electromagnetic waves. Today, many devices use electromagnetic waves as the data transmission medium. Therefore, the frequencies of electromagnetic waves are used to differentiate the functions and purposes of these devices. (Pay attention to the frequencies marked as red.)


(2) Wireless network bands
1) In the table above, there are two frequencyranges that can be used in wireless networks. The detailed ranges are 2.4GHz–2.4835 GHz, 5.725 GHz–5.850 GHz, and 5.170 GHz–5.330 GHz. The bands thatcan be used in wireless networks are 2.4 GHz, 5.8 GHz, and 5.2 GHz.
2) These bands can be classified into 2.4 GHz and 5GHz bands. The differences between the two bands are as follows:


(3) Dual-band devices
1) Phone of older models may support only the 2.4GHz band. When connecting to a Wi-Fi, they can only search for and connect to2.4 GHz signals. Today, many devices support both the 2.4 GHz and 5 GHz bands. That is why some routers, phones, and computers brand themselves as dual-band in the advertisements.
2) Dual-band means that the device supports both the 2.4 GHz and 5 GHz Wi-Fi. When the router transmits 2.4 GHz and 5 GHz signals separately, you need to manually choose a Wi-Fi signal. If 2.4 GHz and5 GHz signals are combined and use the same Wi-Fi name, terminals automatically choose a band when connecting to the Wi-Fi.