Text-to-Speech Voices Including Allison Smith on Asterisk

Cepstral is the only company that offers a Text-to-Speech voice of Allison Smith - the Voice of Asterisk. Our software provides a simple integration making it easy to create dynamic, professional sounding telephony applications. Our customers use Cepstral and Asterisk to power IVR servers, Call Centers, and Unified Communications systems.

Asterisk and Cepstral integration via the app_swift module.

Cepstral Telephony Server

The Cepstral Telephony Server contains the Swift TTS engine, the Lexicon and Cepstral voices. The base software comes with the ability to stream synthesized speech audio to a single call. Add components to create the perfect TTS solution for Asterisk.

Allison Voice

The Allison voice is our flagship voice and matches the voice of Asterisk, Allison Smith, so you can seamlessly blend pre-recorded and dynamically generated TTS audio. Additional voices are available in Spanish and three other languages.

Port Licenses

Stream audio to multiple, simultaneous channels by purchasing Concurrent Port licenses.

Save To File

Produce static content like IVR menu prompts and extension voicemail messages by saving the TTS audio to a WAV file. Choose from multiple frequencies and audio encodings including 8-kHz u-law.


App_Swift is an open source project that integrates Cepstral's TTS engine, Swift, into the Asterisk dialplan. Currently maintained by dOpenSource it relies heavily on previous work by Darren Sessions and Jeremy Kister. App_Swift supports Asterisk 1.4 through Asterisk 16.