Is it any license required in order to use text to speech with 4PSA VoipNow?
Yes, you must purchase at least one voice support license and a concurrency support license. The voice support license allows you to use a certain voice (you can check the current list of voices available at http://www.cepstral.com/downloads/) and the concurrency support license allows you to use the licensed voices from multiple call streams. The concurrency license is global (per server) and several bundles are available (for 3, 10 and 20 concurrent calls). Both the voice support and the concurrency support licenses can be purchased from the 4PSA online store.