I have been building a voice AI receptionist, and there are a lot of terms and acronyms. Some of them are normal telephony acronyms that have been around forever, like DTMF and PSTN (and might need a refresher). Some are AI acronyms, like STT, TTS, LLM and RAG (that we are now sick of hearing every day). Then there are the “glue” terms that only start to matter once you actually try to connect Telephony, Voice and LLMs.
This is my attempt to write down the useful ones, A.K.A The ABCs of Voice AI Agents.

It is not a full architecture doc. It is more of a map of the words that kept coming up while building the bot.