Instructions apply to all currently supported versions of iOS.
Tap the the relevant phone number jot down to add or modify.
A set of new options appears on the screen.
Continue the remainder of the dialing sequence.
TapDoneto secure your changes.
Phone systems treat the comma that you added to the phone number as a pause.
Tap the Pause button two or three times.
Add as many pauses as you oughta match the timing of the phone system.
