Voice terms, in plain English
What each term means in plain words, and how FreJun does it.
Click a term to see its full page.
A
Architecture
Architecture is how the parts of a system fit together and which part is responsible for what. In a voice agent, it covers how the phone call, speech-to-text, the language model and text-to-speech connect to one another.
B
Barge-in
Barge-in is when a caller starts talking while a voice agent is still speaking, and the agent stops so the caller can be heard. It makes a conversation feel natural instead of making the caller wait for the agent to finish.
C
Call Control
Call control means acting on a call while it is still in progress, for example hanging up, muting, playing audio, sending keypad tones or transferring it. It lets software, not just a person, manage a live call.
Call Recording
Call recording saves the audio of a phone call so it can be reviewed later, for quality checks, training or records. Rules about telling people they are being recorded vary by country and state.
Call Transfer
Call transfer passes a live call from one party to another, for example from an AI agent to a person. In a cold transfer, the call is handed over straight away, without briefing the new person first. In a warm transfer, the person handing it over speaks with the new person first.
Concurrency
Concurrency is how many calls are in progress at the same time. It is limited by the capacity of the phone service, often counted in channels, where one channel carries one call.
D
DTMF (Dual Tone Multi-Frequency)
DTMF is the tone a phone makes when you press a key, used for things like "press 1 for sales". Software can detect these tones to read what a caller pressed, or send them to move through another phone menu.
E
Elastic SIP Trunking
Elastic SIP trunking is a SIP trunk whose capacity scales with call volume, so you don't buy a fixed number of lines in advance. Billing is usually based on what you actually use.
I
Inbound Calls
An inbound call is a call that someone makes to your number. The phone service receives it and passes it to whatever is set up to answer, such as a person, a phone system or an AI agent.
L
Latency
Latency is the delay between something happening and the response arriving. In a voice call, it is the gap between someone speaking and hearing a reply, and long gaps make a conversation feel unnatural.
M
Media Streaming
Media streaming sends a call's live audio to another system in real time, usually over a WebSocket, and can play audio back into the call. It is how software such as an AI model listens to and speaks on a phone call.
O
Outbound Calls
An outbound call is a call you place to someone else. Software can start them automatically, for example for reminders or follow-ups.
P
Phone Numbers
A virtual phone number isn't tied to a physical phone line, so calls to it can be sent to software or to any device. Businesses use them to get local, toll-free or mobile numbers in other cities and countries.
S
SIP Trunking
SIP trunking connects a phone system or AI platform to the phone network over the internet, using SIP, so calls go in and out without physical phone lines. The trunk is the connection that carries those calls.
T
Transcription
Transcription turns spoken words into text. In a voice call it can run live, as the audio streams to a speech-to-text service, or afterwards on a recording.
V
Voice API
A voice API lets software place, receive and control phone calls with code. A developer can start a call, stream its audio and act on it while it is live, without building phone infrastructure.
W
Webhooks
A webhook is a message one system sends to another when something happens. A voice platform can send one for each call event, such as a call starting or ending, so your code can react as it happens. A signed webhook carries a signature so the receiver can check who sent it.
Put these terms to work
Get a number, connect your agent, then add call control,
recording or webhooks when you're ready.