How to use your iPhone as a modem

Using a mobile phone as a modem isn't a new feature — in fact, many smartphones came and went before the iPhone had this capability.

Tethering means you don't need a Wi-Fi hotspot or a separate mobile broadband modem to access the Internet on your notebook or PC. Your mobile phone or smartphone becomes the modem and uses your network's 3G data service to connect to the Internet.

Apple's launch of the 3.0 iPhone software in June last year brought tethering to the attention of a broader audience than previously. It used to be used mainly by corporate road warriors, but the decreasing cost of 3G data and the increasingly popularity of smartphones mean that tethering is now more appealing for students, office workers and travellers.

An iPhone can be used as a tethered modem when physically connected to a computer with a USB cable or wirelessly connected via Bluetooth. Follow our step-by-step guide to find out how:

1. Update your software

Before attempting to tether your iPhone, you should ensure you've updated to the latest iPhone software, as well as the latest carrier software. Simply plug your iPhone into your computer, open iTunes and click the "check for updates" button when the iPhone screen appears.

2. Activate tethering

In the iPhone's settings menu, tap General > Network > Internet Tethering. Slide the Internet Tethering switch to On.

3a Connect wired via USB

To tether via USB, first connect your iPhone to your computer. For Windows users, browse to your computer's Network services settings via the Control Panel and choose iPhone. For Mac users (must be running Mac OS X 10.5.7 or later), a pop-up window will appear saying "A new network interface has been detected". Click Network Preferences, configure the network settings for iPhone, then click Apply.

Or: 3b Connect wireless via Bluetooth

In the iPhone's settings menu, tap General > Bluetooth and slide the Bluetooth switch on. Use your computer's Bluetooth menu (Windows: found in Control Panel; Mac: System Preferences) to pair and connect the iPhone to your computer.

5. Browse the Web

When your iPhone is tethered a blue bar appears at the top of the iPhone's screen with the message "Internet Tethering". Tethering remains on if you connect with a USB cable even if you aren’t actively using the Internet. Conveniently, you can still make and receive phone calls and send and receive text messages while tethering.

Ensure you have a large data quota to work with, as tethering uses much more data than browsing the Web on your iPhone does. If you regularly use tethering, we suggest a data allowance of at least 1GB per month.