What Is a Smartphone

by Michael Juntao Yuan
A Smartphone combines the functions of a cellular phone and a handheld computer in a single device. It differs from a normal phone in that it has an operating system and local storage, so users can add and store information, send and receive email, and install programs to the phone as they could with a PDA. A smartphone gives users the best of both worlds--it has much the same capabilities as a handheld computer and the communications ability of a mobile phone.

In this article

  1. Mobile Phones and PDAs
  2. Emergence of the Smartphone
  3. Developing Smartphone Applications
  4. So, What Is a Smartphone?

The word "smartphone" is defined as "a mobile phone that incorporates a PDA (Personal Digital Assistant)" by the Oxford American Dictionary. So, by definition, a smartphone is a converged, multipurpose device. Historically, mobile phones and PDAs have evolved along very different paths. Mobile phones started as dumb voice terminals while PDAs started like mini-PCs. Before we start discussing smartphones, let's have a brief review of how mobile phones and PDAs got to where they are today.

Mobile Phones and PDAs

The original mobile phone was a wireless telephone device primarily for voice communications. Like any other telephone, the mobile phone is only useful when it is hooked into a network and has a service agreement with an operator (a.k.a., a carrier). As a result, mobile phone technology is tightly coupled with the underlying wireless network technologies and the available network services. So far, the wireless network and devices have gone through several generations:

  • The first generation (1G) network is only capable of transmitting voice via analog signals. The handsets are big, heavy, and expensive. Those 1G mobile phones are "dumb" voice-only terminals. 1G networks and mobile phones have been phrased out in most parts of the world.
  • The second generation (2G) network uses digital signal to transmit voice. Compared with analog signal, digital signal is more accurate, reliable, and scalable. As a digital network, the 2G network can carry text messages along with voice. Those text messages, known as SMS (Short Messaging Service), are hugely popular. In addition, a 2G mobile phone often integrates a data modem. It can connect to the internet by making modem calls to certain dial-up service numbers provided by the carrier. Through the internet, a 2G mobile phone can browse the internet via the WAP browser software built into the device.
  • The second and half generation (2.5G) network uses a packet-switch infrastructure to provide always-on internet connections to phones. The data speed in 2.5G network is much faster than that in 2G network. You do not need to wait for the modem to dial and connect. You are not charged for the air minutes for the time you spend browsing the internet. Instead, the data traffic is metered by bandwidth or is simply unmetered with a flat monthly rate. The 2.5G mobile phone supports data centric applications such as email, MMS (Multimedia Messaging Service), and generic web browsing. The 2.5G networks and phones are widely deployed in developed countries.
  • The third generation (3G) network provides very fast data access to the phones. You should be able to enjoy stream audio/video contents on a 3G mobile phone. But the availability of 3G phones and services is still limited.

For PDAs, the story is much simpler. Unlike mobile phones, PDAs do not require subscription-based network services. They are standalone minicomputers, pretty much like PCs before the internet.

The first generation of successful PDAs are Palm Pilots. They primarily function as electronic organizers with support for address books, calendars, email, notes, etc. The PDA only occasionally needs to connect to a companion PC (pairing) for "synchronization." For instance, a PDA can be synchronized with your PC address book, calendar, and email inbox, via a USB or serial cable. Newer PDA models can also connect to PCs wirelessly via Bluetooth, or connect to the internet via WiFi.

A key characteristic that makes PDAs "smart" is that they are programmable. You can use regular computer-programming languages such as C, C++, Java, and BASIC to write PDA applications. In fact, thousands of applications, from medical dictionary to music players to web browsers, have been written for Palm and Microsoft PocketPC PDAs. Those applications are essential for the wide adoption of PDAs. In addition to user-installed software, PDAs can also work with an array of hardware add-ons. For instance, you can attach a thumb keyboard or a GPS unit to a PDA.

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