You ditched your landline years ago. Smart! Because the one thing it was good at—buzzing people into your building—can be done better with your smartphone anyway. Here's how to have that buzzer ring any phone you want.
First, you'll need a Google Voice account. If you already have one, you're halfway there. If you don't have an account, here's a handy guide on how to get one. Once you've got a Google Voice number, give it to your landlord/super to program into your building's buzzer system. Now the when someone rings your apartment buzzer, the call will be routed to the Google Voice account.
Now that your account is set up, head to the Google Voice home page, click on the gear icon in the upper right hand corner and select Settings. Under the Phones tab, add all the phones you want to ring when someone buzzes the front door of your place. Note: You can only have one Google Voice account to assigned to any one number.
Have someone ring your buzzer, and use the number that pops up on caller ID to set up a contact on your phone. Call it Front Door, Buzzer, or The Mighty Drawbridge to Camelot. It's up to you. I assigned the iOS door bell ringtone to the contact for obvious reasons.
Head back to Google Voice and go to the Contacts menu to create a new group, by clicking on the button with two heads and a plus sign. Add your front door's number to this group. You'll use this group to determine which phones will ring when someone buzzes the front door.
Return to Settings in Google Voice and click on the Groups tab. Click on Edit for the Front Door group. Make sure all the phones associated with your apartment—yours, your roommate's, your girlfriend's, whoever—are checked. If you're feeling fancy, you can leave a custom greeting for your Front Door Group to inform callers that no one is home.
That's it. Now when someone arrives with piping hot pizza, they'll hit the buzzer and it'll call all the phones in your Google Voice Front Door group. Anyone can answer, let the person in, and potentially eat all your pizza.
A few bonus uses: Since you you'll be able to let someone into your building from anywhere, if a package arrives while you're away, you can have the delivery driver leave it in the building instead of leaving that stupid note that you have to sign, stick to the door, and pray that they return. Another use for your new front-door-unlocking phone is if you forget your keys. Just buzz yourself into the building and wait for a roommate to let you in your apartment. It's better than standing in the rain.
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