Whether you're frequently calling a friend or loved one who's at extension 123, or you know that to speak to a human in tech support you need to press 2, then 1, then 2 again—you've no doubt faced the annoyance that is dialing said numbers on your iPhone. But there's a better way that doesn't require you toggle the visibility of the keypad after your call first connects.
As The Mac Observer explains, you can add certain details to a contact's phone number to let your iPhone virtually punch the right buttons on its own. When you're editing a contact, you can press the +*# key at the bottom left of the keypad to insert a Pause or a Wait.
As TMO explains, a Pause instructs your iPhone to wait two seconds, and then dial whichever numbers come next. A Wait actually adds a custom button the phone screen, so that you tap a single key to enter in a new series of digits whenever you're ready.
Head over to TMO for the full details of a hint that's a nice update to this one.
Mac OS X Hints