A contact can be saved on a number key and dialed by tapping and holding the key it's saved on. It's easy, but remember you need to save a contact on a speed dialing key before you can use this function.
Step 1 of 3
Use speed dialing
Tap the phone icon.
Step 2 of 3
Use speed dialing
Tap Dial.
Step 3 of 3
Use speed dialing
Tap and hold the required speed dialing key until the number is called.