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CDMA Call Settings

Use these options to enable hearing aid compatibility, and adjust several call settings, such as teletypewriter (TTY) mode.

  1. Tap home key > all apps icon > settings app icon Settings.
  2. Tap Call.
  3. Tap CDMA call settings.

TTY (Teletypewriter) Mode

TTY mode allows people who have hearing or speech impediments to communicate by telephone. HTC U11 is compatible with select TTY phones. Contact your TTY phone manufacturer to see if the phone supports digital wireless transmission. HTC U11 and the TTY phone connect using a special cable that may come with the TTY phone. If this cable was not provided with your TTY phone, contact your TTY phone manufacturer to purchase the connector cable. Most TTY phones connect via a 2.5 mm headset jack adapter. HTC provides a 2.5 mm headset jack adapter that connects to the USB Type-C port on HTC U11. To request this adapter, contact HTC by chat or email at htc.com/us/support.

When establishing your Sprint service, please call Sprint Customer Service using the state Telecommunications Relay Service (TRS) by first dialing 7 key 1 key 1 key call key. Then provide the state TRS with this number: 866-727-4889.

To turn TTY Mode on or off:

  1. Tap home key > all apps icon > settings app icon Settings.
  2. Tap Call.
  3. Tap CDMA call settings > TTY mode.
  4. Tap TTY Full, TTY HCO, or TTY VCO. Tap 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
Sprint 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.

Other CDMA Call Settings

Select these options to enhance voice privacy, prepend numbers automatically, or use plus code dialing.

  1. Tap home key > all apps icon > settings app icon Settings.
  2. Tap Call.
  3. Tap CDMA call settings and select or customize these options.
  • Automatic prepend: Select to automatically add "1" for long distance calls.
  • Plus code dialing: Tap to set plus code dialing. See Place and Answer Calls for details.