Voice & Contact Centre Glossary

Abandoned Call Rate

An abandoned call is one where a live person answers an outbound call and the call is then terminated, for example because no agent is free. Ofcom's persistent misuse policy limits abandoned calls to 3% of live calls on each campaign over 24 hours, including an estimate of AMD false positives.

Source: Ofcom, persistent misuse policy

Agent Assist (AI-Augmented Agents)

Agent assist refers to AI tools that support human agents in real time during calls (suggesting answers, surfacing knowledge and automating after-call notes) to improve speed, consistency and quality without fully automating the conversation.

AHT (Average Handle Time)

AHT (Average Handle Time) is the average total time an agent spends on a customer interaction, including talk time, hold time and after-call work. It is a key efficiency and staffing metric, best managed alongside quality so calls are not rushed.

AI Voice Agent

An AI voice agent is an automated system that holds spoken telephone conversations with customers using natural-language understanding and speech synthesis. Unlike menu-based IVR, it understands free speech, handles multi-turn dialogue, and can resolve routine tasks such as bookings, balances and authentication end to end.

Answering Machine Detection (AMD)

Answering machine detection (AMD) is software in an outbound dialling system that analyses the first moments of audio after a call connects to decide whether a person or a recording answered. Under Ofcom's persistent misuse policy, live people wrongly classed as machines count towards the abandoned call rate.

Source: Ofcom, persistent misuse policy

CCaaS (Contact Centre as a Service)

CCaaS (Contact Centre as a Service) is a cloud contact-centre platform delivered as a subscription, providing call routing, IVR, omnichannel queues, reporting and integrations without on-premise infrastructure. It lets organisations scale contact-centre capability up or down flexibly.

CDR (Call Detail Record)

A call detail record (CDR) is the data a telephone network records for each call: the numbers involved, start time, duration, route and outcome, but not the conversation itself. CDRs drive billing and fraud monitoring and support regulatory requests such as call tracebacks.

CLI (Calling Line Identification)

Calling Line Identification (CLI) is the information that tells the person receiving a call who is calling, usually the caller's number. Under Ofcom's General Condition C6, where CLI is provided it must include a valid, dialable telephone number that uniquely identifies the caller.

Source: Ofcom, CLI guidance

Contact Centre Outsourcing

Contact centre outsourcing is delegating the running of a customer contact centre to a specialist provider, which supplies trained agents, systems and management to handle calls against agreed service levels, usually to reduce cost or add flexible capacity.

Conversational AI

Conversational AI is technology that lets software understand and respond to human language in a natural, back-and-forth way. In contact centres it powers voice agents and chatbots that interpret intent, ask clarifying questions and take actions, rather than following rigid scripted menus.

CSAT (Customer Satisfaction)

CSAT (Customer Satisfaction) is a metric that captures how satisfied customers are with an interaction or service, usually via a short post-contact survey on a rating scale. It is a direct, if subjective, signal of customer experience quality.

DDI (Direct Dial-In)

A DDI (Direct Dial-In), also called a DID, is a telephone number that routes directly to a specific person, team or line within an organisation without going through a switchboard. Businesses provision blocks of DDIs to give staff or services individual numbers.

DID Origination

DID (Direct Inward Dialling) origination is the supply of inbound telephone numbers whose calls are delivered from the public network to a customer's own network or platform. Wholesale providers supply DIDs in bulk to carriers and resellers; in the UK the same kind of number is usually called a DDI.

FCR (First Contact Resolution)

FCR (First Contact Resolution) is the percentage of customer issues resolved on the first interaction, without the customer needing to make contact again. It is widely regarded as one of the strongest indicators of both customer satisfaction and operational efficiency.

FNOL (First Notification of Loss)

FNOL (First Notification of Loss) is the first contact an insurance customer makes to report a claim. Handling it well means capturing accurate details quickly while treating a potentially distressed customer with care: a common target for AI-assisted or outsourced handling.

IVR (Interactive Voice Response)

IVR (Interactive Voice Response) is an automated phone system that interacts with callers through recorded prompts and keypad or voice input, routing them to the right department or self-service option. Modern IVR can use speech recognition and skills-based routing to reduce wait times.

NLP (Natural Language Processing)

NLP (Natural Language Processing) is the field of AI concerned with enabling computers to understand, interpret and generate human language. In contact centres it powers speech-to-text, intent detection, sentiment analysis and conversational voice agents.

Number Porting

Number porting is the process of transferring an existing telephone number from one provider or network to another, so a business can change supplier without changing its published numbers. In the UK it typically takes a few working days to complete.

Omnichannel

Omnichannel contact means handling customer interactions consistently across multiple channels (phone, email, chat, messaging and social) with shared context, so a customer can move between channels without having to repeat themselves.

PSTN Switch-Off

The PSTN switch-off (the UK's 'big switch-off') is the planned withdrawal of the traditional analogue phone network and ISDN lines, with services moving to internet-based voice such as SIP and VoIP. Openreach has targeted completion for the end of January 2027.

Source: Openreach, the big switch-off

QoS (Quality of Service)

QoS (Quality of Service) refers to network techniques that prioritise voice traffic over other data so calls stay clear and uninterrupted. Proper QoS configuration is essential for reliable VoIP and SIP call quality on a shared internet connection.

Service Level (80/20)

Service level in a contact centre is the percentage of calls answered within a target time, commonly expressed as '80/20', meaning 80% of calls answered within 20 seconds. It measures accessibility and is monitored in real time to manage staffing.

SIP Trunking

SIP trunking delivers telephone calls over an internet or data connection instead of traditional ISDN lines, connecting a phone system to the public network. Capacity is measured in channels (concurrent calls) and can be scaled in software without installing physical lines.

Speech Analytics

Speech analytics is technology that automatically transcribes and analyses recorded or live calls to detect topics, sentiment, compliance issues and agent behaviours. It lets contact centres review 100% of calls instead of a small manual sample, supporting quality, compliance and coaching.

STIR/SHAKEN

STIR/SHAKEN is the caller ID authentication framework the US Federal Communications Commission requires for calls carried over IP networks. The originating provider digitally signs the caller ID and the terminating provider verifies it, which makes spoofed numbers easier to detect and trace.

Source: FCC, caller ID authentication

TPS and CTPS

The Telephone Preference Service (TPS) and the Corporate Telephone Preference Service (CTPS) are the UK's statutory registers of people and organisations who do not want live marketing calls. Under PECR, callers must check numbers against them first; a new registration can take 28 days to take effect.

Source: ICO, rules on live marketing calls

UCaaS (Unified Communications as a Service)

UCaaS (Unified Communications as a Service) is a cloud-delivered platform that combines business telephony, video, messaging and collaboration in one service. It removes on-premise phone hardware, scales on demand, and typically integrates with tools such as Microsoft Teams.

Voice BPO

Voice BPO (Business Process Outsourcing) is the practice of contracting an external provider to run some or all of your telephone-based customer contact (inbound support, outbound campaigns, or both) using the provider's agents, technology and quality processes on your behalf.

Voice Termination

Voice (call) termination is routing an outbound call from one network to its destination network so it can be completed. Wholesale providers connect to many carriers and route each call over the best path, balancing cost and quality, often called A-Z termination for global coverage.

VoIP (Voice over Internet Protocol)

VoIP (Voice over Internet Protocol) is technology that carries voice calls as data over the internet rather than traditional phone lines. It underpins SIP trunking, hosted phone systems and softphones, and generally lowers cost while adding flexibility and integration.

VoIP Reseller (White-Label VoIP)

A VoIP reseller sells voice services (SIP trunking, cloud telephony or call termination) to end customers under its own brand, using a wholesaler's network and platforms. White-label VoIP is the same service delivered under the reseller's brand rather than the wholesaler's.

Wholesale VoIP

Wholesale VoIP is the bulk supply of voice connectivity (call termination, origination and interconnects) to other providers such as carriers, resellers and ISPs rather than to end users, typically priced per minute or per channel at wholesale rates.