First Android phone unveiled

The first mobile phone to use Google's Android software has been unveiled, as the internet giant takes on Apple and the established phone makers.

The T-Mobile G1, made by the Taiwanese company HTC, was launched at an event in New York on 23 September. It will go on sale in the United States next month and in Britain in the autumn.

The phone

The G1 has a touch screen that slides up to reveal a full keyboard, and a small trackball for moving around the screen. It includes a camera, GPS for maps and directions, and a web browser, and it works on the fast 3G networks.

The phone is closely linked to Google's own services, including Gmail, Google Maps and YouTube, and users will be able to download extra programs from an online shop called Android Market.

Open software

Android is an operating system for mobile phones, which Google announced last year along with a group of phone makers, networks and chip companies known as the Open Handset Alliance.

Unlike Apple's iPhone software, Android is open source, which means any phone maker can use it free of charge and adapt it to their needs. Software developers can also create programs for it without needing to ask permission.

Google hopes this approach will lead to a wide range of Android phones from different manufacturers, helping it to reach more people with its services and advertising.

The smartphone race

Smartphones, which can browse the web, send email and run programs, are a fast-growing part of the phone market. Apple's iPhone, launched last year, has been a huge success, and its App Store, opened in July, has already attracted thousands of programs.

Other companies, including Nokia, Research In Motion, the maker of the BlackBerry, and Microsoft, are also competing for a share of the market.

Early reviews

Reviewers have praised the G1's keyboard and its links to Google's services, but have criticised its design and battery life, and say it lacks some of the polish of the iPhone.

Analysts say Android's success will depend on how many manufacturers adopt it. Several, including Samsung, Motorola and Sony Ericsson, have said they are working on Android phones.

For Google, the phone marks a major step into a market that is expected to become one of the most important in technology.