HTC Desire 816 User Manual page 209

Hearing Aids
Select the Hearing aids option to enable hearing aid compatibility that amplifies your phone's in-call
volume.
1. With two fingers, swipe down from the status bar, and then touch
2. Select the Hearing aids option.
TTY Mode
A TTY (teletypewriter, also known as a TDD or Text Telephone) is a telecommunications phone
that allows people who are deaf, hard of hearing, or who have speech or language disabilities, to
communicate by telephone.
Your phone is compatible with select TTY phones. Please check with the manufacturer of your TTY
phone to ensure that it supports digital wireless transmission. Your phone and TTY phone will
connect using a special cable that plugs into your phone's headset jack. If this cable was not provided
with your TTY phone, contact your TTY phone manufacturer to purchase the connector cable.
When establishing your Virgin Mobile service, please call Virgin Mobile Customer Service using the
state Telecommunications Relay Service (TRS) by first dialing
provide the state TRS with this number: 866-727-4889.
To turn TTY Mode on or off:
1. With two fingers, swipe down from the status bar, and then touch
2. Touch TTY Full, TTY HCO, or TTY VCO. Touch TTY Off to turn TTY mode off.
Note: When enabled, TTY mode may impair the audio quality of non-TTY phones connected to the
headset jack.
Warning: 9-1-1 Emergency Calling
Virgin Mobile recommends that TTY users make emergency calls by other means, including
Telecommunications Relay Services (TRS), analog cellular, and landline communications. Wireless
TTY calls to 9-1-1 may be corrupted when received by public safety answering points (PSAPs),
rendering some communications unintelligible. The problem encountered appears related to TTY
equipment or software used by PSAPs. This matter has been brought to the attention of the FCC,
and the wireless industry and the PSAP community are currently working to resolve this.
DDTM Mode
Select this option if you want to direct all calls to your voicemail when you are using data connection.
Voice Privacy
Select to enable enhanced privacy mode.
Automatic Prepend
Select to automatically add "1" for long distance calls.
Settings
> Call.
. Then
> Call > TTY mode.
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