If you need a second number that will still ring through to your smartphone, you might consider the Google Voice app. Subscribers to the service can also make phone calls using this second number, and send/receive text messages. The second phone number could be used for personal calls, or if you have a business that you don’t want to have connected with your personal number, you can use the second phone number for that. This way, calls made to your business number will be sent directly to your smartphone even if you’re on the go.
