Two Messaging TUI options interfere with the signaling between Messaging and TTY devices. TTY device users cannot use TUI features that:
Adjust the playback speed of a voice message.
Skip forward or backward within a message while the message is playing.
For example, if you change the playback rate of a Messaging TTY message, you also change the baud rate of the transmission. Messaging and the receiving TTY device are no longer synchronized. 
Note
Note These TUI features might not be available for your TUI.
For more information about TTY related troubleshooting, see Troubleshooting the TTY user interface.