Smartphones are devices designed for communication and connectivity. This means that their primary function is communication. Smartphones come with a range of tools that help them carry out this function.

Communication and connectivity entails being able to access mobile broadband as well as the internet, and connect to other electronic devices like other smartphones, Bluetooth headsets, smartwatches, smart TVs etc.

The main connections used by phones include Bluetooth, Wi-Fi, Internet/mobile broadband, USB and infrared technology.

As you may have noticed, all of the following except one are wireless. The shift from using wired communications to wireless started as far back as the 1980s. Modern smartphones today are almost all wireless except for their charging ports (the high end phones have wireless charging). These were all made possible by the addition of radios and modems to the smartphone. Sometimes these radios are embedded into the SoC, other times they are attached to the motherboard outside of the SoC.


Bluetooth is a wireless standard used for exchanging data between fixed (e.g Personal Computers) and/or mobile devices (e.g. smartphones) over short distances. It was introduced in 1989. Bluetooth was first used in phones in 2001 appearing in the Ericsson T36.
It quickly became popular and replaced the older and slower Infrared means of inter-device communication.

The Ericsson T39 (credits: Wikipedia)


1. File sharing: Its major use was for file transfer e.g. documents, multimedia etc. but it is only used for transfer of small files these days as file sizes have gotten bigger and it is impracticable to send them via Bluetooth.
2. Interconnectivity between devices: this is now the primary use of Bluetooth technology especially in this age of IoT (Internet of things). Inter device connection includes headset to smartphone, smartphone to smartwatch, printer to PC, smartphone to PC or printer, video game consoles to controllers (game pads) etc.


The first generation Bluetooth radios, Bluetooth version 1.0 was released in 1999. It had a speed of 1 Mbps (mega bit per second) which is equivalent to 0.125 megabyte per second. It’s range was very short (10 meters) and it consumed a lot of battery. It could also only connect to one device at a time. Bluetooth 1.0B (2001), Bluetooth 1.1 (2001) and Bluetooth 1.2 (2003) only came with very minor improvements.

Bluetooth logo (credits: Wikipedia)

The second generation or Bluetooth 2.0+ EDR (Enhanced Data Range) was released in 2004 and was an improvement on the first generation. It could transfer data at 2 to 3 Mbps (0.25 to 0.375 MB/s) but it didn’t improve on the range or battery consumption. A slight upgrade known as Bluetooth 2.1+ EDR was released in 2007.

The third generation promised much and delivered on it’s promise at the expense of huge battery consumption. The version 3.0+ HS (High Speed) is still used by many headphones today because it transferred data at speeds of up 24Mbps (3 MB/s) and consumed a lot of battery as well.

The fourth generation took a totally different approach and was aimed at low energy devices like fitness trackers, smartwatches, mice and keyboards, true wireless (TWS) earbuds etc. The version 4.0 LE (Low Energy) was released in 2010. Version 4.0 transfers data at 1Mbps. Further revisions included the 4.1 (2013) and 4.2 (2014).

The current generation is Bluetooth version 5.0. It improves on 4.0 by increasing data transmission speeds but maintaining low power consumption. Bluetooth 5.0 has data transmission speeds of 2 Mbps and a range of 240 meters which when compared to the old 10 meter range is massive. Current iterations include Bluetooth 5.1 and 5.2.


This is a family of wireless network protocols based on the IEE802.11 family of standards for Local Area Networks (LAN) and Internet Alliance. It is the wireless equivalent of Ethernet (a wired internet connection). Wi-Fi uses a radio antenna and bands (just like Bluetooth) to transmit data (files or internet).

Wi-Fi can send data over very large areas and it works best if there is no obstruction between the access point (or hotspot) and the receiver. A smartphone Wi-Fi hotspot has a range of 20 to 150 meters. Like any wireless network, it is less secure than wired connections. This is why most people are advised against using unsecure Wi-Fi connections in public places so as prevent them from being hacked and their data stolen.


Inter device connectivity: Wi-Fi is used to connect two devices wirelessly.

File Sharing: A lot of apps have been developed to take advantage of this. The most popular of these is Xender which took over from a one time favorite, Flash Share. Wi-Fi can be used to send large amounts of data within a fairly short time.

Internet Sharing: Wi-Fi can also be used to share internet connectivity between two devices with one acting as a hotspot (host) and the other acting as a receiver. Examples include phone to phone internet data sharing via hotspot as  well as a Wi-Fi router to a Smartphone or PC.

Screencasting: Newer smart TVs come equipped with Wi-Fi. The regular TVs that do not come with Wi-Fi can be fitted with a Wi-Fi receiver to which audiovisual data from your smartphone or laptop can be streamed to your TV set.

City wide internet: Many cities in first world countries have city wide internet where internet is transmitted to the populace by the means of powerful routers strategically placed all over the city. These could be free, subsidized or paid for.

Geo location: The position of a phone can be pinpointed by locating the nearest Wi-Fi which a phone is connected to.


Infrared ( or IR for short) wireless is the use of wireless technology to send/transfer data. It is used for short and medium range connections.

Infrared rays are generated by the phone as pulses of light which are focused through a piece of semi-transparent plastic called an IR blaster. This piece of plastic is then aimed at the receiving device which accepts the information. The IR blaster is usually found at the top of the phone.

An IR blaster on the Redmi Note 9 Pro


IR technology is very old and was once used on phones as the primary method of file sharing but it was painfully slow and was soon replaced by Bluetooth in the early 2000’s. it is used these days to turn smartphones into universal remotes for household and/or car appliances.

This brings us to the very end of this post, thank you for reading to the end.