Falling under the category of mobile devices, today's consumer electronics serve multiple purposes. Years ago, cellular phones, also called cellphone or mobile phone, served one purpose only: They let you send and receive voice communications. Today, mobile phones and similar devices are equipped with customized software, Internet access, digital cameras, portable music players, GPS functions and many more options.
Once again technological advancements make common terminology such as mobile phone, smartphone, PDA and PDA phone difficult to decipher as each type of device changes constantly and features traditionally belonging to one type of device are now found on others. Here we will explore the popular category of mobile communication devices, the similarities and differences between some of the popular products.

What Is a Mobile Phone?
A mobile phone is more frequently called a cellular phone or cellphone. These communication devices connect to a wireless communications network through radio waves or satellite transmissions. Most mobile phones provide voice communications, Short Message Service (SMS), Multimedia Message Service (MMS), and newer phones may also provide Internet services such as Web browsing, instant messaging capabilities and e-mail.

What Is a PDA?
Short for personal digital assistant, this is the name given to small handheld devices that combine computing, telephone/fax, Internet and networking features. A typical PDA can function as a cellular phone, fax sender, Web browser and personal organizer. These devices are usually pen-based, which requires the use of a stylus rather than a keyboard for input. PDAs today are available in either a stylus or keyboard version. Traditionally, PDAs have not had phone or fax services.

What Is a Smartphone?
A smartphone is considered to be the combination of the traditional PDA and cellular phone, with a bigger focus on the cellular phone part. These handheld devices integrates mobile phone capabilities with the more common features of a handheld computer or PDA. Smartphones allow users to store information, e-mail, install programs, along with using a mobile phone in one device. A smartphone's features is usually more oriented towards mobile phone options than the PDA-like features. There is no industry standard for what defines a smartphone, so any mobile device that has more than basic cellphone capabilities can actually be filed under the smartphone category of devices.

What Is a PDA Phone?
It's definitely a lack of standardization that makes the category of mobile devices so confusing to the consumer. As technology changes, so do the functions that these different devices perform. Years ago, many people differentiated PDA and smartphone simply by looking for touch-screen capabilities. If it had a touch screen it was a PDA, if it didn't, it was a smartphone.  The Sony Ericsson Smartphone, for example, offers users both a touch screen and a full QWERTY keyboard.  Despite the fact that the manufacturer calls this product a smartphone, the generic term for a PDA oriented device with cellular phone capabilities is called a PDA phone.

Fuzzy Lines Between Smart Devices
Even if you can now decide for yourself if a mobile device is simply a cellular phone, a smartphone, a PDA or PDA phone, the fine lines between these types of mobile devices are about to get blurred again as we add in new terms to the mix like Pocket PC, and Smartphone (with a capital letter).

So starting with the difference between smartphone, as we've discussed above: When capitalized, it refers to Microsoft's Smartphone platform, which is used for a variety of mobile devices. The latest version, Windows Mobile 6 actually removes the word Smartphone from its title, and over time this should help lessen the confusion between smartphone and Smartphone. Interestingly, , one of the three versions of Windows Mobile 6 is called Windows Mobile 6 Standard for Smartphones. Here the "For Smartphones" means "phones without touch screens".

The Pocket PC itself is not a specific category of mobile devices, but rather the name given to PDAs that use the Microsoft Windows Mobile operating system. Much like the category of PDA devices, Pocket PCs features are focused on computing and data tasks with other features, like cellular phone capabilities being secondary to the PDA functions.  The Pocket PC is one device that is standardized. In order to carry the Pocket PC label the device must meet specific criteria such as use Microsoft's Windows Mobile for Pocket PCs, include a touch screen, include a touchpad, and other specifications.

Some Popular Examples

The popular Apple iPhone is a combination smartphone and iPod

The HP iPAQ Mobile Messenger is a Pocket PC

The LG Prada is a cellular phone with a touch screen — but its not a smartphone

The RIM BlackBerry 8800 is considered a smartphone — but its borderline on being a handheld PC device due to its size and features

The Palm Treo 700p is a PDA phone

The Motorola Q is also considered to be a PDA phone

What's The Differences, Again?
In summing up the differences between these common mobile communications devices you could say that a PDA phone is more PDA than phone and a smartphone is more phone than PDA. And, of course, a cellular phone is more phone than anything else.