palmOne Vision Smart Device Treo 650 User Manual page 173

5. Select OK. A red T appears at the top of the Phone screen whenever TTY is
enabled.
Important
Sprint recommends that TTY users make emergency calls by other means, including
Notice
Telecommunications Relay Services (TRS), analog cellular, and landline
communications. Wireless TTY calls to 911 may be corrupted when received by public
safety answering points (PSAPs), rendering some communications unintelligible.
Sprint PCS Service Features—The Basics
TTY Enabled
161