If you have to call a lot of people who have extension numbers, you know how frustrating that can be. Do you write down their extension numbers in your Contacts app? If so, where? Do you just have to remember every single one? Ugh.

Yeah, this way doesn't work.

Fortunately, the iPhone has a built-in, simple way that you can add a customized button for dialing someone's extension. That's a pretty great idea, right? To set one up, find a contact with an extension number you'd like to add, and then click the Edit button on his or her card to make changes. When you start editing a phone number, you'll see a button labeled +*# at the lower left.

Touch that, and you'll get this screen, which'll allow you to put in either a "pause" or a "wait" for the number in question.

A pause adds a two-second delay, which is indicated by a comma.

You can add as many pauses as you like, and then you'll type in the extension at the end. So if you know, for example, that a certain business makes you wait six seconds before you can punch in someone's extension number, just insert three pauses as I've done above, and your iPhone will dial the extension for you after that amount of time.

Adding a wait, though, is where the magic happens. This'll be indicated by a semicolon instead of a comma, but you'll type the extension in afterward, same as before.

Instead of pausing a certain number of seconds, a wait will add a special button that you can press when you're calling someone to go to the extension.

Just like with the pauses, you can add multiple waits, too. So you could type in "800-867-5309;123;456;789," and the first button that appears will be "Dial '123,'" followed by "Dial '456'" after you press the first one, and so on. That'd be very handy for walking through automatic systems without having to switch over to the keypad at all.

Neat! So no more trying to remember extensions or—God forbid—actually talking to another human being to ask him to put you through. I shudder at the thought.