The voice AI vocabulary, defined plainly.

AI voice infrastructure

Voice AI delivered as a layer underneath an organisation’s existing telephony rather than as an application it migrates onto. The practical test is what the buyer has to change: infrastructure requires no new phone provider, no ported numbers, no hardware and no new tool for staff to log into, and it writes into the systems already in use. An application asks you to move your workflow to it. Prime Assist is built and sold as infrastructure.

AI receptionist

A voice agent that answers inbound phone calls in natural speech, completes routine requests end to end, and hands anything else to a human. Distinct from an IVR, which only routes, and from a chatbot, which is text based. More in what is an AI receptionist?

AI voice agent

The broader term for software that holds a spoken conversation over the telephone. An AI receptionist is a voice agent configured for inbound reception work. Outbound voice agents make calls instead. Prime Assist answers inbound calls and messages; it does not make outbound calls.

Answering service

A service that answers an organisation’s calls from outside the building, usually with people working to a script who take a message or pass the call on for the organisation’s own staff to deal with. An AI receptionist differs in that it completes routine requests on the call itself. How the two compare: AI receptionist vs human answering service.

Audit trail

A timestamped record of every action taken on a call: what was asked, what was said, what was booked and when a human was involved. Required in regulated settings and useful in any dispute.

Barge-in

The ability for a caller to interrupt the agent mid-sentence and be understood. Its absence is the single most obvious sign of an unnatural voice system.

Better Purchasing framework

NHS England’s Advanced Telephony Better Purchasing framework, through which GP practices in England buy cloud-based telephony. Every system on it offers at least the core functionality of the national telephony specification, and every supplier on it must give practices reporting on their calls, as NHS England’s guidance on improving telephone journeys in general practice explains (updated 28 May 2024). NHS England’s advice to practices on virtual (AI) receptionists (26 February 2026) quotes the GP contract: practices will be required to buy their telephony only from the framework once their current telephony contracts expire.^{1Note 1: when the sources were checked}

Call forwarding

A telephone feature that sends calls made to one number on to another: every call, only when the line is busy or nobody answers, or at set times, depending on the phone system. The number callers dial does not change, and forwarding can be switched off again. The phone provider may charge for forwarded calls. How Prime Assist connects to a phone system: integrations and phone systems.

Clinical Safety Officer

The named clinician accountable for the safety case of a health IT system under NHS standards. Prime Assist has one: Dr Humzah Jessa, a practising doctor. Vendors that do not make health IT are not required to have one.

Data controller and data processor

Under UK GDPR, the controller is the organisation that, alone or jointly with others, decides the purposes and means of processing personal data, and is ultimately in charge of and responsible for that processing. A processor processes personal data on the controller’s behalf and, under Article 29, only on the controller’s instructions unless the law requires otherwise. A processor may sub-contract some of the processing to another processor, sometimes called a sub-processor. The ICO’s guidance on controllers and processors explains how to tell which you are.^{2Note 2: when the source was checked}

DCB0129

The NHS clinical risk management standard for manufacturers of health IT. Compliance requires a documented hazard log, a safety case and a named Clinical Safety Officer. Prime Assist has a clinical safety case under it, signed off by its Clinical Safety Officer. More in DTAC, DCB0129 and DSPT explained, and on our clinical safety and data protection page.

DCB0160

The NHS clinical risk management standard for organisations that deploy and use health IT, such as NHS trusts, primary care organisations and social care providers. DCB0129 covers the manufacturer of a product; DCB0160 asks the organisation putting it into use to assess and manage the clinical risks of doing so in its own setting, and, like DCB0129, to name a Clinical Safety Officer, as NHS England’s guidance on digital clinical safety assurance says. Both are information standards published under section 250 of the Health and Social Care Act 2012, and NHS England is reviewing them, as its supporting information for its review of the standards explains (published 29 June 2026).^{1Note 1: when the sources were checked}

DPIA

Data protection impact assessment: a process to identify and minimise the data protection risks of a project. Under UK GDPR an organisation must carry one out for processing that is likely to result in a high risk to individuals, as the ICO’s guidance on DPIAs explains. Prime Assist supplies a DPIA template with its written data processing agreement.

DSPT

The NHS Data Security and Protection Toolkit, an annual self-assessment against national data security standards required of organisations handling NHS patient data. For Prime Assist, the DSPT is submitted, and the evidence is shared with buyers on request. More in DTAC, DCB0129 and DSPT explained.

DTAC

The Digital Technology Assessment Criteria used by NHS organisations to assess clinical safety, data protection, technical security, interoperability and usability before buying a digital product. NHS England refreshed the form in March 2026, with fewer questions and less overlap with the DSPT, and the earlier form has not been used since 6 April 2026. For Prime Assist, the DTAC is completed, and the evidence is shared with buyers on request. More in DTAC, DCB0129 and DSPT explained.

Escalation

The defined handover of a call from the voice agent to a human. In a serious product escalation runs on explicit written triggers with a named route, not on the agent’s judgement in the moment.

First-call resolution

The share of calls where the caller’s need is fully met on that call, with no callback, message or second contact. The most honest measure of whether a phone system works.

ICB

Integrated care board: the NHS organisation responsible for planning health services for the population of one area of England, managing the NHS budget there and working with local providers such as hospitals and GP practices, as NHS England describes it. There is one ICB in each integrated care system (ICS) area. Some ICBs are being merged and their boundaries changed, with changes taking effect in April 2026 and April 2027, so the ICB that covers a practice can change.

IM1

Interface Mechanism 1: NHS England’s IM1 pairing route, through which a third-party product can connect to a principal GP clinical system, such as Optum’s EMIS Web or TPP’s SystmOne, to read patient information, extract it in bulk or enter data. The product’s supplier pairs separately with each clinical system supplier, and the product is tested and assured before NHS England issues a recommendation to connect. Prime Assist’s connections to EMIS and SystmOne through IM1 are live. More in how AI phone answering connects to EMIS and SystmOne through IM1.

IVR

Interactive voice response, the press-one-for-sales menu tree. IVR classifies and routes callers but resolves nothing itself, so it always ends in a queue, a voicemail box or a hang-up. How the two compare: AI receptionist vs IVR menu and voicemail.

Latency

The delay between a caller finishing speaking and the agent replying. When the pause runs noticeably longer than it would with a person, the conversation starts to feel wrong, however good the voice sounds.

National telephony data

The call data that GP practices in England provide through their cloud-based telephony. NHS England’s advice to practices on virtual (AI) receptionists quotes the GP contract’s requirement to provide data on eight metrics through a national data extraction, and says providing that national data set sits within the practice’s contract with its Better Purchasing framework telephony supplier. It asks practices using a virtual receptionist to check how the national reporting will be delivered.^{2Note 2: when the source was checked} NHS England Digital publishes the national figures as Cloud Based Telephony Data in General Practice, official statistics in development, the source of the GP figures on our facts page.

NHS Spine and the Personal Demographics Service (PDS)

NHS Spine is the national IT infrastructure that joins up health and care IT systems in England, Wales and the Isle of Man, and hosts national services such as the Personal Demographics Service. The Personal Demographics Service (PDS) is the national master database of NHS patients’ basic details, such as name, address, date of birth, registered GP and NHS number, and it is reached through authorised clinical and patient applications rather than directly. Prime Assist’s NHS Spine connection, for Personal Demographics Service lookups, is in progress.

Number porting and call diversion

Two ways an organisation’s calls can reach another service. Porting moves the phone number itself to another supplier or carrier. Diversion, or call forwarding, keeps the number with the organisation’s own telephony supplier and sends calls on to another number. NHS England’s advice to practices on virtual (AI) receptionists asks GP practices to consider carefully before porting their number to a third party that is not their contracted telephony supplier, because that goes against the national requirements for telephony, and notes that forwarding calls to a third party may bring extra charges from the telephony supplier.^{2Note 2: when the source was checked} Prime Assist never requires number porting.

Out-of-hours

In UK healthcare, the time when a GP practice is closed. For GP practices in England, the GMS contract regulations define the out of hours period as 6.30pm to 8am on Monday to Thursday nights, 6.30pm on Friday to 8am on Monday, and Good Friday, Christmas Day and bank holidays. When the practice is closed, NHS 111 can direct patients to the right place for help, such as an out-of-hours GP. Dental and veterinary practices have their own out-of-hours duties: see how a dental practice should handle urgent calls and how a vet practice should handle out-of-hours calls.

PCN

Primary care network: a group of GP practices in England working together, and with community, mental health, social care, pharmacy, hospital and voluntary services, for their local area. NHS England describes PCNs as typically serving 30,000 to 50,000 people, and practices take part through the Network Contract Directed Enhanced Service (DES).

SIP trunk

A connection that carries a phone system’s calls to and from the telephone network over a data connection, using the Session Initiation Protocol (SIP), in place of traditional analogue or ISDN lines. One trunk can carry several calls at once, and it can link an on-premise or cloud phone system to a telephone provider.

Task completion

Whether the call ended with the job actually done in your systems, as opposed to a message being taken. The distinction between an AI receptionist and an answering service.

Transcript

The written record of a spoken call. Used for audit, quality review, dispute resolution and, in a well-integrated deployment, written straight into the customer or patient record.

UK or EU data residency

A UK or EU processing region, committed by contract: the customer chooses the United Kingdom or the European Union, and call data is stored and processed there. Distinct from a vendor saying it uses a UK or EU region, which can change without notice.

Virtual receptionist

Someone, or something, that answers a business’s calls from outside the building. In the UK the term often means a person at an outsourced answering service, who takes a message and passes it on. NHS England’s advice to GP practices uses virtual (AI) receptionist for the automated kind, which this glossary calls an AI receptionist. How the two compare: AI receptionist vs human answering service.

Warm transfer

Passing a live call to a human along with the context of the conversation so far, rather than dropping the caller into a cold queue to explain everything again.

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