Resolution
To disable Text to Speech (TTS) playback of emails when voicemails are checked on the Cisco Unity server, check the subscribers Class of Service settings, and disable TTS.
To do this, go to the Cisco Unity System Administration web page (SAWeb) > Subscribers > Class Of Service > Features and uncheck the check box for Text to Speech for E-Mail Messages. For information on disabling the TTS playback for Cisco Unity 4.x, refer Class of Service Features Settings section of the document Class of Service Settings.
This document applies to Unity 3.x and Unity 4.x
