(By Chris Scoble, managing director at Nashua Mobile)

Like many South Africans, you may be carrying a cutting-edge smartphone in your pocket that is packed with the latest bells and whistles, yet use it for little more than voice calls and text-messaging.

If so, you are losing out on a range of powerful mobile data services and applications that can help you to be more productive wherever you are. Perhaps you were scared off by the jargon around mobile data, or are unsure of what the various services and technologies do.

In this article, I'll define some of the most common terms that you'll encounter in the mobile data world, then look at the cost implications of using your cellphone to access Internet services.

Common terms:

GPRS - or General Packet Radio Service - is the entry-level cellular data technology. Because GPRS has been around for years, it's widely available across South Africa and is supported by most phones in the market today.

However, it offers download and upload speeds that are comparable to a dial-up modem, making it suitable only for tasks such as downloading ringtones, sending emails without attachments, sharing low-resolution multimedia messages, and other tasks that aren't particularly demanding.

EDGE - Enhanced Data for GSM Evolution - is the next step up the ladder. An evolution from GRPS, it is four times faster than GPRS and offers data speeds of up to 240kb/second. This technology delivers a far better user experience when downloading larger files, browsing rich Websites, and other bandwidth intensive tasks than does GPRS.

3G - third-generation cellular technology - enables operators to offer users a wider range of more advanced services than they could in the past. By comparison to its predecessors, 3G is blazingly fast with a speed of about 384kb/second. 3G has subsequently evolved into High Speed Downlink Packet Access (HSDPA) - theoretically capable of speeds as high as 3.6 MB/second - and High-Speed Uplink Packet Access (HSUPA), which runs at up to 7.2 MB/second. These technologies bring cellular data services closer to the performance of fixed-line broadband technologies such as ADSL.

Let's briefly consider the amount of time it would take to download a 1 MB file on each of these technologies at their theoretical maximum speeds:

It gets complicated

The theoretical maximum speeds of each technology are subject to a range of factors: how busy the network is, whether the signal has to pass through brick, concrete, glass, and other obstructions, and international bandwidth traffic. However, the basic point stands: higher-speed services allow you to do more interesting things with your phone, like watching YouTube videos or sending bigger email attachments.

It's important to check which of these network technologies your phone supports - a 3G cellphone will not automatically give you access to EDGE or HSDPA, so shop wisely when you upgrade your handset.

Also, try to find out what technologies your operator offers in the regions where you spend most of your time. The newer technologies such as HSUPA are generally rolled out first in larger metropolitan areas.

If you have a smartphone that supports these technologies, you'll be able to link it to a PC via BlueTooth or a cable, giving you a way to access to the Internet from your notebook wherever you are or a back-up for a landline that is down.

So how much does it cost?

Data access is priced in megabytes (MBs), and the cost is standard across access technologies such as GPRS, EDGE and 3G.

Depending on the package you opt for, mobile data can cost you anything from R0.20/MB to R1.85/MB on a contract bundle. Obviously, the more megabytes you buy in your contract bundle, the less you pay per megabyte.

A Vodacom bundle that offers you 250MB of data bolted onto your existing contract will cost you R159/month. So, what can you do with that? With 100MB, you can download about 20 songs, receive 333 emails with documents or low-res images attached, receive 10,000 text emails, spend about four hours browsing Facebook, or log in to Internet banking and complete transactions about 250 times.

If you opt for a BlackBerry Internet Service package from MTN or Vodacom, you'll pay as little as R59/month for unlimited usage of email and the Internet from your BlackBerry device.

As you can see, mobile data is extremely affordable. Once you start receiving emails and browsing the Web on-the-go, you'll wonder how you ever got by without mobile data on your handset.