Hiawatha Bray

After years of wasting our time with built-in cameras, music players, and casual games, cellphone makers are finally giving us something we really need: One plug to charge them all. Next year, the world?s leading phone manufacturers will adopt a universal interface, so that one power adapter will charge any phone.

But the most important telephone interface is nowhere near universal. I refer, of course, to the phone number. We?ve got home numbers, work numbers, cell numbers, sometimes several of each. They all do the exact same job, only with different phones. What we need is a universal phone number that can ring any or all of our phones.

And soon you?ll be able to get one, courtesy of Google Inc. The company has begun rolling out Google Voice, a service to let us manage our telephonic lives through a single, internet-connected phone number. There?s no charge, although you still have to pay for your regular phone services.

Go to voice.google. com to sign up for a free account. The service is still in trial mode, with new users being added a few thousand at a time. But that was also true of a little Google service called Gmail when it launched five years ago; today it?s used by more than 100 million people. Google Voice could someday be at least as popular. Google didn?t originate the concept. In 2007, it bought GrandCentral, a start-up that issued phone numbers the way the government hands out Social Security cards. The GrandCentral number didn?t belong to a particular phone or phone company; it belonged to you, for life.

GrandCentral had planned to charge a monthly fee for its services. But Google makes its money from selling advertising on its various websites. It merely needs to keep us coming back to those sites, with features and services we?ll come to regard as indispensable – such as a master control system for all our telephones.

Log onto Google Voice and you can select a new phone number. You can pick up the area code, taking one that suggests you?re in Atlanta, Los Angeles, or Boise, if available. (Google eventually hopes to offer ?number portability,? which would let you use one of your existing phone numbers as your Google Voice number. But for now, you have to take the number Google assigns you.)

Next, you punch in the numbers of the various phones you have already. Now you can have Google Voice manage call routing to each phone. You can have all your phones ring when a call comes in, so you can answer the nearest one.

You can even choose by caller name. Say your spouse dials your Google Voice number. The system recognises the phone number and routes the call only to your cellphone. You can also record a custom voice mail message for your sweetheart only.

When a stranger dials your Google Voice number, the system asks for his or her name before making the connection. When you answer the call, it tells you who?s calling and lets you choose to send the call straight to voicemail and you can use the slick ?listen in? feature to eavesdrop as the message is being left. If it sounds interesting enough, you can break in and take the call. Google Voice can also make a recording of incoming calls, after warning the caller that his words are preserved.

Google Voice will transcribe messages using speech-to-text software, and you can have messages sent to you via e-mail or to a cellphone with SMS text messaging. The original audio is preserved, and you can listen to it by phone or through your computer.

But you?ll have to keep checking for messages on your various phones, even after you?ve given your Google Voice number to all your friends. They could be skipping over Google Voice and calling your old numbers directly. So much for a single, standardised phone number.

Google Voice could become a major rival to the popular internet calling service Skype. A lot of people use Skype software to make cheap international calls over their personal computers. With Google Voice, you can do the same thing over any standard phone.