We literally use FreePBX for mainly this function. We went with Amazon Polly for TTS. We added the TTS variables as variables in the call file, then use the Polly TTS command to read it in the dialplan to the callee.
It is very cost effective, and more importantly there is a guide to get it all setup. IT works extremely well. My hope is one day FreePBX will have a module to make adding these TTS services easier.
Whew, that thread is daunting. If you got that going from that my hat off to you. I am going to give that a try but not being a programmer (although I have access to a few) makes it difficult. Thanks again.
OK last reply and I will leave you be. I saw no reference to a call file anyone was using for that. Can you post an example? All the digging I did I could not find any variables for using TTS in a call file.
Also not a programmer, and I can tell you once you get started it is nowhere near as daunting as it appears to be.
This entry in the thread summarizes how to make Polly a TTS engine in the GUI. You can make your call file point to a context in the GUI, then start using the TTS from the GUI, using the variables you have stored in the call file.
Otherwise as jerson mentioned, you need to put a context that references it in the call file.
The guy in this post put everything in an php script as another option to try.