I've been meaning to write something up about this NY Times article for a while — around a month, I guess — and I'm finally getting around to it. GrandCentral has set up a service wherein you can sign up for a single phone number, which you would give out in lieu of publicizing your “real” numbers — your home phone, office phone, mobile phone, and any others you might have. That single number will serve as a filter and router, giving you control over who reaches you when, and at which telephone.
Callers are filtered by the telephone numbers they're calling from (so the system is susceptible to caller-ID spoofing). You give the system your telephone numbers. You set up contact groups, and put known phone numbers into the groups. Then you decide, globally and by group, which of your telephones should ring when a phone in each group (or an unknown one) calls you. All of your selected phones will ring at the same time.
When you answer one of the ringing phones, the system announces your caller and asks whether you want to accept the call. This allows both call screening and protection against having one of your answering machines grab the call (if, for example, your office phone goes to voice-mail before you manage to find and answer your mobile). If you accept the call, you're connected, and your other phones stop ringing.
You can set the system up so that, say, calls from your family and from your kids' schools ring all your phones, calls from your co-workers only ring your office phone, calls from your spouse's friends only ring your home phone and your spouse's mobile, and so on. It also has some features that might turn out to be more cute than useful — you can choose, by group, what the caller hears while waiting for you to answer. It might be nice to tell friends and family that you're on vacation, but not tell others that, so there's clearly some use. I wonder, though, whether I'll take any real advantage of that.
The trickiest bit, I think, will be deciding how to handle unknown callers. On the one hand, you might want to be more restrictive about where they get to, only sending them to one phone, or sending them directly to voice-mail (GrandCentral has its own voice-mail subsystem). On the other hand, if your son's teacher calls in an emergency, and calls from a phone that you haven't programmed ahead of time, it wouldn't get through. Everyone's preference will differ here, but it seems that the safest thing is to have unknown calls ring all phones — you can always screen the calls and send them to voice-mail yourself.
I've been interested in a service like this for some time, and have wondered why the telephone companies haven't provided it (and patented aspects of it, in fact). I'll play with GrandCentral for a while before I decide whether I want to use it. One disagvantage for now is that they have numbers available in only a limited set of area codes (so, for instance, I signed up with a Manhattan area code because they don't have numbers in Westchester County). There's also the question of whether they'll start charging for it when it's fully in production service, and how much the charge will be.
Try it out. If you do, comment here and tell me what you think.