Voice AI and call center glossary

AI phone agent

An AI phone agent is a voice agent connected to the phone network.

Large language model

A large language model (LLM) is a neural network trained on huge amounts of text to predict the next token in a sequence.

Prosody

Prosody is the pattern of pitch, rhythm, stress, pace, loudness and pausing that shapes how speech sounds beyond its words.

Speech-to-speech model

A speech-to-speech model is a single model that takes spoken audio as input and produces spoken audio as output, without a separate speech-to-text or text-to-speech step.

Backchanneling

Backchanneling is the short feedback a listener gives while another person holds the floor, such as "mm-hm", "right" or "okay".

Barge-in

Barge-in is a caller speaking while the agent is still talking.

Guardrails

AI guardrails are controls placed around an LLM that limit what it says and does, such as blocking off-topic requests, restricting tools, or checking output before it is spoken.

Hallucination

AI hallucination is when an LLM generates text that is nonsensical or unfaithful to the source it was given, or states things with no support.

Knowledge base

A knowledge base is a collection of documents, such as FAQs, policies and product pages, that a voice agent can search while answering a caller.

Retrieval-augmented generation

Retrieval-augmented generation (RAG) is a method where a system first retrieves relevant passages from a document collection, then gives them to an LLM along with the question so the answer is based on that text.

System prompt

A system prompt is the standing text an LLM receives before the conversation begins, setting its role, tone, goals and limits.

Tool calling

Tool calling is when an LLM, instead of answering in words, returns a structured request to run a named function, such as looking up an order.

Webhook

A webhook is an HTTP request that one system sends to a URL on another system when something happens or is needed.

Answering machine detection

Answering machine detection, or AMD, is the step on an outbound call that decides whether a person or a machine, such as voicemail, picked up.

Call recording

Call recording is saving the audio of a phone call, usually with a transcript, so it can be reviewed later.

Caller ID

Caller ID is the calling number, and sometimes a name, that the network sends with a call so the recipient's phone can display it.

Cold transfer

A cold transfer is a call handoff that sends the caller straight to another number or queue without the first party speaking to whoever answers.

Concurrent calls

Concurrent calls are the calls that are connected at the same moment.

DID number

Direct inward dialing number

A DID number, short for direct inward dialing, is a phone number that outside callers can dial to reach a specific line, extension or voice agent directly.

DTMF

DTMF, or dual-tone multi-frequency signaling, is the way a phone reports a key press.

Inbound calling

Inbound calling is the handling of calls that customers place to a business.

Outbound calling

Outbound calling is when a business starts the call, phoning customers or prospects for sales, reminders, collections or surveys.

Predictive dialer

A predictive dialer is software that places more calls than there are free human agents, using the expected answer rate and call length to guess how many will be answered.

PSTN

The PSTN, or public switched telephone network, is the worldwide set of interconnected carrier networks that route calls between telephone numbers.

SIP trunking

Session Initiation Protocol trunking

SIP trunking is a way to connect a phone system, or a voice agent, to the public phone network over an IP connection to a carrier.

STIR/SHAKEN

STIR/SHAKEN is the framework US carriers use to sign calls with a digital certificate and verify that the caller ID is genuine.

Toll-free number

A toll-free number is a phone number, such as an 800 or 833 number, where the called party pays for the call instead of the caller.

Warm transfer

A warm transfer is a call handoff in which the first party speaks to the receiving person, explains the caller's situation, and only then connects the caller.

WebRTC

Web Real-Time Communication

WebRTC is a set of web standards and protocols that let browsers and apps send real-time audio, video and data directly between devices.

After-call work

After-call work (ACW) is the wrap-up a customer support agent completes after the caller hangs up, such as writing notes, updating the customer record, choosing a call outcome and scheduling follow-ups.

Average handle time

Average handle time (AHT) is the mean time spent on a customer contact, from the moment it is answered to the end of any wrap-up work.

Average speed of answer

Average speed of answer (ASA), also called speed to answer, is the average time between a call entering the queue and being answered by an agent.

Call abandonment rate

Call abandonment rate is the share of calls that end before the caller is helped.

Containment rate

Containment rate is the share of calls that an automated system, such as an IVR or a voice agent, handles from start to finish without transferring to a human.

Cost per call

Cost per call is the total cost of handling a set of calls divided by the number of calls handled.

CSAT

CSAT, or customer satisfaction score, is the share of survey respondents who rate a specific interaction as satisfied.

Deflection rate

Deflection rate is the share of customer contacts that are resolved or absorbed by self-service or automation before they reach the live agent queue.

Escalation rate

Escalation rate is the share of calls that an automated system hands off to a human agent.

First call resolution

First call resolution (FCR) is the share of customer issues that are solved during the first contact, with no follow-up call, callback or repeat contact about the same problem within a set window.

Net Promoter Score

Net Promoter Score (NPS) is a loyalty metric built from one question, how likely a customer is to recommend a company, answered on a 0 to 10 scale.

Resolution rate

Resolution rate is the share of customer contacts in which the customer's problem was actually solved, whether by an automated system, a human or both.

Service level

Service level is the percentage of calls answered within a target number of seconds.

AI disclosure

AI disclosure is telling a person that they are talking to an automated system, not a human.

Data retention

Data retention is how long an organization keeps data and the rule for when it deletes it.

GDPR

General Data Protection Regulation

GDPR is the EU regulation, Regulation (EU) 2016/679, that governs the processing of personal data by organizations established in the EU, and by those elsewhere that offer goods or services to people in the EU or monitor their behaviour there.

HIPAA

Health Insurance Portability and Accountability Act

HIPAA is the US federal law whose Privacy, Security and Breach Notification Rules govern protected health information held by covered entities and their business associates.

PCI DSS

PCI DSS is the Payment Card Industry Data Security Standard, a set of technical and operational requirements for entities that store, process or transmit payment card data.

SOC 2

System and Organization Controls 2

SOC 2 is an attestation report from an independent CPA firm on a service organization's controls for security and, optionally, availability, processing integrity, confidentiality and privacy.

TCPA

Telephone Consumer Protection Act

TCPA is the US federal law, 47 U.S.C. 227, that limits calls made with an autodialer or an artificial or prerecorded voice, and telemarketing calls.

Zero data retention

Zero data retention is a vendor configuration in which a service processes audio or text to return a result and does not store the inputs or outputs afterward.

Agent assist

Agent assist is software that helps a human customer support agent during a live call, by transcribing the conversation, suggesting answers, pulling up knowledge articles and filling in forms.

Answering service

An answering service is a third party that answers a business's phone calls when its own staff cannot, takes a message or follows a short script, and passes urgent calls on.

Appointment setting

Appointment setting is the work of agreeing a date, time and purpose with a caller and recording it in a calendar.

First notice of loss

First notice of loss, or FNOL, is the first report to an insurer that a loss has happened, such as a car accident or water damage.

Human in the loop

Human in the loop is a design in which a person takes part at defined points of an automated process, by approving an action, taking over a task, or reviewing results afterward.

Lead qualification

Lead qualification is the step that decides whether a prospect fits what a company sells and is ready to talk to sales, based on a few criteria such as need, budget, authority and timing.

No-show rate

No-show rate is the percentage of booked appointments where the customer or patient neither attends nor cancels in time.

Omnichannel

Omnichannel is a way of running customer support so that voice, chat, text and email share one customer record and one conversation history.

Right-party contact

Right-party contact (RPC) is an outbound call connected to the actual person the caller meant to reach, as opposed to a voicemail, a wrong number or another household member.

Speed to lead

Speed to lead is the elapsed time between a prospect asking to be contacted, for example by submitting a web form, and the first live conversation with them.

Virtual receptionist

A virtual receptionist is a remote person or software that does a front-desk job by phone: greeting callers, answering common questions, routing calls and booking appointments.