Connecting Mobile Devices – CompTIA A+ 220-1101 – 1.3

There are many ways to connect a mobile device with computers, headphones, and speakers. In this video, you’ll learn about USB connections, serial interfaces, NFC, Bluetooth, and more.


The amount of technology in a single phone or tablet is remarkable. And in this video, we’ll talk about connectivity for those particular devices. There’s both wired and wireless options for connectivity on our phones, on our tablets, and we have seen many changes to the standards and the way that we connect to those devices through the years.

We use this connectivity to perform a number of different functions. Not only connectivity to the internet, being able to obtain our email and browse the net, but we also use it for backup and identification and in some cases to synchronize our systems with all of the other devices that we use.

For the majority of our phones and our tablets, we use USB or Universal Serial Bus as the primary wired connection type. USB is designed for high speed communication and it’s often used to connect our mobile device with our computer or with a power source. You’re probably already familiar with the larger type A plug that we often see on computers. The device itself may have a different type of USB connection.

If you have an older device, it may be connecting over USB with this mini B plug. Many of today’s mobile devices using this type of connectivity will use the smaller micro B plug. And indeed, that’s a very common standard across many mobile devices. This is not the only way to connect and charge our mobile devices, but this tends to be some of the more common connections that you’ll find.

Newer phones and tablets use a USB connection, but it’s a different type of connector, specifically a USB-C connector USB-C is used on both devices and the computer. So you may find that your device has fewer type A plugs these days and more of the smaller USB-C plugs. The USB-C standard defines what this plug looks like, but you could put lots of different types of signals over that single interface. For example, the USB-C plug may be sending display port signals. It may provide HDMI video and audio. Or you may be sending Thunderbolt data over a USB-C physical connection.

If you have an Apple device, you might not be using any of those USB connections. You may instead be using a Lightning connection. This is an eight pin proprietary connection from Apple and it’s commonly seen on iPhones and iPads. There are a number of advantages that lightning has over the micro-USB. One is that this Lightning connection supports a higher power output, which allows us to charge our phones and our tablets that much faster. This is also a type of connector that can be inserted either way, which was a problem prior to the advent of USB-C.

What this means for you as a technician is that you’ll probably have a lot of different cables in your tool bag. You might be walking around with cables that are designed for a USB, mini-USB, micro-USB, or Lightning connectors just so you’re able to plug in and connect to whatever you might find.

Before the advent of universal serial bus, we still use serial communication, but it was using different interfaces. Commonly it would use a DB-9 interface. This is a nine pin connection. Sometimes you’ll see this referred to as a DE-9 connection. These serial cables commonly transported RS232 signals. And this is a standard of communication that’s been around for a very long time. You can probably still find devices in your infrastructure that use DB-9 connections with RS232 to be able to connect and view consoles on switches, routers, and other devices.

Before USB was invented, this was the serial connection that we used for almost everything on our computers. So if you needed to plug-in a modem or a mouse, then you were probably using DB-9 over the serial connection. These days we see a lot more USB and a lot less DB-9 in our environments. But if you still have an older switch or router around, then you’ll probably need a serial cable with a DB-9 connector at the end so that you’re able to configure that device. If you look at your laptop today, you probably won’t even find a DB-9 connector. Instead you’ll have to get a conversion cable that will use one of your USB interfaces, convert it to a DB-9 physical connection so you can send those serial signals over to a switch router or anything else that might need this type of serial connection.

A very popular mobile connection type is NFC. NFC is Near Field Communication and it’s a way to send small amounts of data between devices that are located very close to each other. If you’ve ever gone into a store and used a payment system or you needed to transfer information between two mobile devices, then you’re probably using NFC to facilitate that conversation. You can also use NFC as an access device, or something like an identification card that you could hold up to a sensor and use it to unlock an electronic door.

You can’t have a conversation about mobile device connectivity without including Bluetooth. It is probably one of the most popular wireless communication methods we use with our mobile devices. If you’re using wireless earbuds or a wireless headset or you’re connecting to the audio system of your automobile, then you’re probably using Bluetooth.

You may be used to using a Wi-Fi hotspot at your local coffee shop. But you can also use many mobile phones as a wireless hotspot. You can enable that wireless hotspot functionality on your mobile phone and now anyone around you can connect your mobile phone over 802.11 and your mobile phone will use your wireless provider’s network to be able to gain access to the internet.

Not all phones support this Wi-Fi hotspot connectivity, and your phone provider may require you to pay extra each month just to enable that capability on your phone. Either way, it’s another option that you can use to be able to gain access to the internet from devices that may only have 802.11 access. Either way, it’s a method you can use to enable your 802.11 devices to be able to gain internet access where there may not be a public access point available