Glossary
AI phone assistant
An AI phone assistant is software that answers calls on its own, understands spoken language and replies in conversation.
Also: voice agent, AI phone agent, AI telephony
Technically, three building blocks work together: speech recognition turns what was said into text, a language model words the reply, and speech synthesis speaks it. Newer systems process speech directly, without the detour through text. On top of that come the telephone connection, a knowledge base with the information of the business, and interfaces to a calendar or CRM.
Typical tasks are information on opening hours and services, appointment booking, taking down requests for a callback and transferring to a human. Unlike a keypad menu, the assistant does not follow a fixed tree but responds to freely worded sentences. It reaches its limits where knowledge is missing or where a decision is reserved for a person.
At Call0
Call0 builds the assistant from your website and lets you test it in the browser free of charge (15 test minutes). It answers questions from approved knowledge, books appointments and hands over to your team.
Related terms: AI answering machine · Voicebot and IVR · Knowledge base and RAG · AI receptionist
As of: 6 October 2026