When working online, it's a simple matter to open a new browser tab and quickly look something up, or to send an instant message to a friend. Ditech Networks, based in Mountain View, CA, hopes to bring the same kind of functionality to phone calls. The company has developed technology that lets users access certain applications in the middle of a mobile phone call.

The divide between the Internet and the phone system has already begun to blur. Voice over Internet Protocol (VoIP) technology allows voice to run alongside other kinds of Internet traffic. Smart phones that offer easier access to the Web have introduced Web applications with voice functionality--for example, Google's voice-activated search iPhone application or a voice-based note-taking service that works with any cell-phone, offered by Seattle company Jott.

Ditech hopes to let users access many more applications without even having to take the handset away from their ears. "What we're really doing is . . . starting to make voice and phone calls truly a digital technology," says Todd Simpson, CEO of the company. Ditech's system, called the mStage platform, is a layer of software that a mobile carrier adds to its network. Once mStage is installed, users can access a voice service by saying certain keywords. For example, in the course of a conversation about meeting for dinner, a user might want to search for the nearest pizza place. A keyword, such as the name of the pizza chain, could trigger a menu from which the user could select a search application to return results within the call. The platform can also insert a quick message into a user's phone call--for instance, briefly breaking in to whisper a meeting notification in the user's ear.

To demonstrate how other software could connect to the mStage platform, Ditech has created a compatible Facebook application. Assuming mStage is implemented by cell-phone carriers, the app will show when a user is on the phone and let her friends send messages into those calls. Simpson says that this could serve as a way to quickly update a friend about evening plans, without completely interrupting her current call.