Mobile Device Accessories and Ports
Depending on what you need to accomplish with your mobile device, you might require a wired or a wireless connection. Let’s discuss these now.
Wired connections use physical ports. If you have ever plugged in a mobile device to charge it, then you have used a wired connection.
The most common wired connection is USB. USB has been around for a long time and has gone through several versions and port changes. USB is used by devices that run Android and Windows (among others). However, aside from USB-C, iOS-based devices from Apple use the proprietary Lightning connector. Figure 3.1 shows examples of the ports and connectors that you should know for the exam, including Mini-USB, Micro-USB, USB-C, and Lightning.
FIGURE 3.1 USB and Lightning ports and connectors
Almost all device charging cables use a standard Type A USB port on the other end, regardless of the connector type that is used to attach to the device. This allows connectivity to the majority of charging plugs and PCs and laptops in the world. However, there are tons of adapters out there, so be ready.
As of the writing of this book (2022), USB-C is common for many Android-based smartphones and tablets. Previously, and for many years, Android devices used Micro-USB, but USB-C has been the dominant port on new devices since at least 2019. Even some Apple devices started using it in 2019. On the other hand, Mini-USB is quite uncommon, but you might see it on older devices, such as accessories for smartphones.
Another purpose of a wired port is to make it possible to tether the mobile device to a desktop or laptop computer (usually via the computer’s USB port). This tethering can allow a desktop computer or laptop to share the mobile device’s Internet connection. Tethering functionality can be very useful in areas where a smartphone has cellular access but the PC/laptop cannot connect to the Internet. Once the physical USB connection is made, USB tethering can be turned on in the OS settings (where you will usually find the Mobile Hotspot option as well). Keep in mind that Wi-Fi capability on a smartphone is usually disabled when USB tethering is enabled and that the user must have hotspot service with their cellular provider for USB tethering to work.
Some mobile devices can also be equipped with serial interfaces (RS-232) or adapters from USB to serial. This allows for testing of devices and connectivity to various networking equipment and industrial devices. We will discuss serial interfaces and RS-232 in Chapter 13.
Wireless technologies are what really make a smartphone attractive to users. Most people would rather do without cables, and technologies such as Bluetooth, near-field communication (NFC), and hotspots make a smartphone functional and easier to use.
Given the inherent mobility of smartphones and tablets, most technologies regarding communications and control are wireless. If designed and configured properly, wireless connections offer ease of use, efficiency, and even great speed. We’ll discuss Wi-Fi, cellular, GPS, and similar data-related wireless technologies later in the book. For now, let’s focus on wireless connections used by mobile devices to communicate with accessories and other mobile devices.
One of the wireless technologies most commonly used is Bluetooth. Bluetooth enables users to incorporate wearable technology (such as headsets, earpieces, earbuds, and smartwatches) with their existing mobile devices. But the technology goes much further; for example, it allows for the streaming of music to external speakers and an automobile’s music system. Bluetooth is usually limited to about 33 feet (10 meters), which is the maximum transmission distance for Class 2 Bluetooth devices.
Another commonly used wireless technology is the mobile hotspot. When enabled on a properly equipped smartphone or tablet (with 4G or faster connection), a hotspot allows a user to connect desktops, laptops, and other mobile devices (wirelessly, of course) through the device running the hotspot, ultimately allowing access to the Internet. This can be a great way to connect your laptop or other computer if Wi-Fi goes down, often with speeds rivaling wired Internet speeds. But remember, there’s usually a catch! Many providers charge for data usage (unless you have a corporate plan). Because of this, a hotspot is often used as a secondary connection or as a backup plan. In addition, the further the hotspot-enabled mobile device is from a cell tower, the lower the data transfer rate. So know the pros and cons of running a hotspot on a mobile device.
Next, let’s discuss near-field communication (NFC). This allows smartphones to communicate with each other via radio frequency by touching the devices together or, in some cases, by simply having them in close proximity to each other. NFC uses the radio frequency 13.56 MHz and can transmit 100 to 400 kb/s. It doesn’t sound like much—it transfers more slowly than Bluetooth, for example—but it’s usually plenty for sending and receiving contact information, MP3s, and even photos. Besides working in peer-to-peer mode (also known as ad hoc mode), a full NFC device can also act like a smart card performing payment transactions and reading NFC tags. If you are not sure whether your device supports NFC, check the settings in the mobile OS. Most smartphones incorporate NFC technology.