The mobile industry is working on a common way to turn cameraphones into barcode readers.

A few companies already offer applications that let cameraphone users capture a bar code in order to send more information to the user, and this technology is widely used in Japan. But the CTIA since late last year has been working on a way to unify efforts so that a company that displays a barcode can expect all phones to be able to read it.

In a brief demonstration on Thursday at the CTIA conference in San Francisco, Jeff Giard, a product marketing manager at Alltel, showed how someone might interact with a barcode displayed on a movie advertisement in a bus shelter. He launched the barcode reader application on his phone and then waved the camera over the barcode. Immediately, his phone began to download a trailer for the movie.

In the future, the advertiser could add information at the end of the trailer about which nearby theaters are showing the film and when, he said.

Advertisers can display the barcodes on large images like the one in the bus shelter or smaller advertisements in magazines or newspapers, he said.

A white paper released by CTIA this week described other possible scenarios. A video game advertisement could feature a barcode and offer a phone user a preview of the game and a coupon to buy it at a local retailer. Bands could use barcodes in advertisements to direct people to online sites where they can buy concert tickets.

Swiping the barcode could also launch a pre-populated SMS (short message service) text message, initiate a phone call or create a calendar entry.

The scenario sounds similar to one once discussed by proponents of Bluetooth. Some people imagined advertising campaigns that would push messages out to phone users as they passed by billboards equipped with Bluetooth. Security concerns helped slow down that development. The barcode effort might be inherently more secure because it requires users to proactively launch an application and swipe the barcode before receiving any data.