The common components found on all phones are:
- A CPU, the processor of phones.
- A battery, providing the power source for the phone functions.
- An input mechanism to allow the user to interact with the phone. These are a keypadfor feature phones and touch screens for most smartphones.
- A display which echoes the user's typing, and displays text messages, contacts, and more.
- Speakers for sound.
- SIM cards and R-UIM cards.
Low-end mobile phones are often referred to as feature phones and offer basic telephony. Handsets with more advanced computing ability through the use of native software applications are known as smartphones.
Central processing unit
Mobile phones have central processing units(CPUs), similar to those in computers, but optimised to operate in low power environments.
Mobile CPU performance depends not only on the clock rate (generally given in multiples of hertz)[17] but also the memory hierarchy also greatly affects overall performance. Because of these problems, the performance of mobile phone CPUs is often more appropriately given by scores derived from various standardized tests to measure the real effective performance in commonly used applications.
Display
One of the main characteristics of phones is the screen. Depending on the device's type and design, the screen fills most or nearly all of the space on a device's front surface. Many smartphone displays have an aspect ratio of 16:9, but taller aspect ratios became more common in 2017.
Screen sizes are measured in diagonal inches; feature phones generally have screen sizes below 3.5 inches. Phones with screens larger than 5.2 inches are often called "phablets." Smartphones with screens over 4.5 inches in size are commonly difficult to use with only a single hand, since most thumbs cannot reach the entire screen surface; they may need to be shifted around in the hand, held in one hand and manipulated by the other, or used in place with both hands. Due to design advances, some modern smartphones with large screen sizes and "edge-to-edge" designs have compact builds that improve their ergonomics, while the shift to taller aspect ratios have resulted in phones that have larger screen sizes whilst maintaining the ergonomics associated with smaller 16:9 displays.[18][19][20]
Liquid-crystal displays are the most common; others are IPS, LED, OLED, and AMOLEDdisplays. Some displays are integrated with pressure-sensitive digitizers, such as those developed by Wacom and Samsung,[21] and Apple's "3D Touch" system.
Sound
In sound, smartphones and feature phones vary little. Some audio-quality enhancing features, such as Voice over LTE and HD Voice, have appeared and are often available on newer smartphones. Sound quality can remain a problem due to the design of the phone, the quality of the cellular network and compression algorithms used in long distance calls.[22][23] Audio quality can be improved using a VoIP application over WiFi.[24]Cellphones have small speakers so that the user can use a speakerphone feature and talk to a person on the phone without holding it to their ear. The small speakers can also be used to listen to digital audio files of music or speech or watch videos with an audio component, without holding the phone close to the ear.
Battery
The average phone battery lasts 2–3 years at best. Many of the wireless devices use a Lithium-Ion (Li-Ion) battery, which charges 500-2500 times, depending on how users take care of the battery and the charging techniques used.[25] It is only natural for these rechargeable batteries to chemically age, which is why the performance of the battery when used for a year or two will begin to deteriorate. Battery life can be extended by draining it regularly, not overcharging it, and keeping it away from heat.[26][27]
SIM card
Mobile phones require a small microchipcalled a Subscriber Identity Module or SIM card, in order to function. The SIM card is approximately the size of a small postage stamp and is usually placed underneath the battery in the rear of the unit. The SIM securely stores the service-subscriber key (IMSI) and the Ki used to identify and authenticate the user of the mobile phone. The SIM card allows users to change phones by simply removing the SIM card from one mobile phone and inserting it into another mobile phone or broadband telephony device, provided that this is not prevented by a SIM lock. The first SIM card was made in 1991 by Munich smart card maker Giesecke & Devrientfor the Finnish wireless network operator Radiolinja.[citation needed]
A hybrid mobile phone can hold up to four SIM cards, with a phone having an IMEI per SIM Card. SIM and R-UIM cards may be mixed together to allow both GSM and CDMAnetworks to be accessed. From 2010 onwards, such phones became popular in emerging markets,[28] and this was attributed to the desire to obtain the lowest on-net calling rate.