Google Voice is an online service that is capable of unifying several communications channels under a single phone number. That way, when that number gets a call, several phones can ring at once. It isn't simply a VoIP service like its rival Skype. However, it still uses VoIP technology for many of its functions, such as allowing users to make free local calls, cheap international calls and when routing incoming calls.
When you sign up for the Google Voice service, you're given a phone number called a Google number. You can also port in an existing phone number to use with the service, but several conditions apply. When someone calls you on your Google number, you have several ways of handling the call.
By signing in to your Google Voice account, you'll be presented with a wide range of configuration settings. The most interesting and useful one is a feature that lets you set which phones will ring whenever you get a call on your Google number. Currently, the system supports up to six phone numbers, which means that you can set up to six different phones or devices to ring when you get an incoming call. For example, you can have your home and mobile phone ring.
Another great feature of the Google Voice service is that you can customize which phones will ring at which time. For instance, you can set your office phone to ring during the day, while sending calls to your smartphone in the evening.
Google Voice uses a combination of VoIP technology and the regular PSTN (traditional landline telephone system). When you receive a call on your Google number, the call is first sent to Google's system, then redirected to the phone number you've set to ring, such as your home, mobile or office phone.
Related: Google Voice Alternatives
While the Google Voice service in itself is free, it's not a complete alternative to using a landline or mobile phone. Unlike with other services like Skype, you'll still need to keep your service with your landline or mobile carrier.
However, you can save money by using Google Voice in many other ways. The service allows you to make free calls to any number in North America (US and Canada). While many other communications services let you make unlimited local calls, few of them are free. Those who frequently make calls outside of North America will be happy to see that the service allows users to make very affordable calls to international destinations. The per-minute rates vary depending on the destination country, but tend to be many times cheaper than if you had used your mobile or home phone.
There are many features that come with Google Voice that most other communications providers would charge for. Examples include voicemail, call forwarding, caller ID and call screening. Google Voice also comes with free SMS, which gives you the ability to send text messages to mobile users without paying.
One unfortunate limitation of Google Voice is that the service is currently only available in the United States. However, it's believed that Google may eventually roll it out in other countries in the future. Overall, it's a good communication service if you want to have one number that allows you to be reached everywhere. However, if you're looking to replace your home or office phone service with a VoIP alternative, you'll likely find other services more suited for your needs.
Related: Grasshopper vs. Google Voice
