HTC DROID Incredible - Manual (Page 73)

Phone calls 
Auto Retry
When enabled, the phone automatically redials a number when the
attempted call fails.
TTY mode
Allow the use of a TTY (teletypewriter) device for users who are
visually or hearing impaired.
Hearing aids
Turn on the Hearing Aid Compliance feature that reduces interference
to hearing aids.
Phone settings
Edit the call reject message, choose whether to open the message
editor when you reject a call with a message, and choose whether to
allow automatic saving of an unknown contact number when a call
with that number ends.
NBPCD
Set the calling parameters for the current country, such as country
code and IDD prefix.
Assisted Dialing
Assisted Dialing allows you to easily dial international calls while
roaming in another country. See “Using Assisted Dialing” in this
chapter for details.
Voice Privacy
Encrypts outgoing voice calls and uses secure channels when
available.