Millions of people have more than one phone number these days — home, work, cellular, hotel room, vacation home, yacht — and with great complexity comes great hassle. You have to check multiple answering machines. You miss calls when people try to reach you on your cell when you’re at home (or the other way around). You send around e-mail messages at work that say, “On Thursday from 5 to 8:30, I’ll be on my cell; for the rest of the weekend, call me at home.”

And when you switch your job, cellphone carrier or home city, you have to notify everyone you know that you have new phone numbers.

A new service called GrandCentral, now in its final weeks of public beta testing, solves all of these problems. It’s a rather brilliant melding of cellphone and the Internet.

Its motto, “One number for life,” pretty much says it all. At GrandCentral.com, you choose a new, single, unified phone number (more on this in a moment). You hand it out to everyone you know, instructing them to delete all your old numbers from their Rolodexes.

From now on, whenever somebody dials your new uninumber, all of your phones ring simultaneously, like something out of “The Lawnmower Man.”

No longer will anyone have to track you down by dialing each of your numbers in turn. No longer does it matter if you’re home, at work or on the road. Your new GrandCentral phone number will find you.

GrandCentral in a nutshell

1. “One number for life”. Users pick one out of probably 20 given by GrandCentral. Users then can assign upto 6 numbers to this new number; when a call comes in, all phones will ring simultaneously.
2. No applications to download. Just a computer with internet connection.
3. How much? It’s FREE with unlimited incoming calls and core features.

What can users do with GrandCentral?

1. Customized greetings — Record a different voice mail greeting for each person in your address book. Specify, on a per person basis, which phone rings, which ringback music plays and whether the call goes directly to voice mail.
2. Web button — Install a “call me” button on Web site — a great, free way to field calls from eBay, MySpace or dating-service Web page.
3. Quick changes — With a quick click at GrandCentral.com, direct all calls to voice mail; direct all calls to a new, temporary number (like a hotel); or prevent home line from ringing during work hours.
4. Record calls — Users can record a conversation at anytime by pressing 4 on the phone, and pressing 4 again discontinues recording.
5. Switch lines — Anytime during a call, press the * key to make all phones ring again, so that users can pick up on a different phone in midconversation without the other person knowing.
6. Listen in voice messages — Don’t want to pick up? Press 3 to listen in while someone’s leaving a message. Press * to pick up the call.
7. Ringback Music — Replace the ringing sounds the caller hears while waiting with music—in GrandCentral’s case, any MP3 file of choice.

All of this works smoothly and quickly, and the Web site does a noble job of organizing that dizzying number of functions. And all of these features are free, even those that would be expensive or unavailable from your phone company.

Downsides

1. Local numbers might not be available. So neighbors would have to call long distance
2. Specific numbers require annual fees.
3. GrandCentral offers a huge list of additional features that aren’t so simple. If you’re not careful, GrandCentral can turn into a full-blown hobby.

nytimes.com