Card machine glossary
The terms that appear on a card machine contract, a merchant statement and the regulator's directions, each defined in plain English.
Definitions only. Where a figure appears (the contactless limit, the interchange caps, the 18-month term) it is taken from the regulator or the legislation and listed under Sources at the foot of the page, checked August 2026. For the numbers providers charge, see the fee comparison and card machine costs explained. Funding terms are in the separate business funding glossary.
Acquirer
The payment company or bank that processes card transactions for a business and settles the money to its bank account. Acquiring is a regulated payment service; under the FCA's perimeter guidance, supplying a terminal on its own is a technical service rather than acquiring. The card machine agreement is ultimately with the acquirer, even when a reseller supplied the terminal.
Blended pricing
A pricing model where the provider charges one percentage on every transaction regardless of card type, with interchange, scheme fees and margin rolled together. Simple to read, harder to compare line by line.
Interchange++ (interchange plus plus)
A pricing model where the interchange fee, the card scheme fee and the acquirer's margin are shown as three separate lines. Each transaction is priced on its actual card type.
Interchange fee
The portion of a card transaction paid to the cardholder's bank. In the UK it is capped at 0.2% for consumer debit and 0.3% for consumer credit cards under the Interchange Fee Regulation, where merchant, acquirer and issuer are all in the UK.
More on this →Interchange Fee Regulation (IFR)
The retained EU regulation (2015/751) that caps interchange on UK consumer card transactions. It has applied since 9 December 2015 and is enforced by the Payment Systems Regulator.
Card scheme
The network that carries a card payment between acquirer and issuer: Visa, Mastercard, American Express and others. Each scheme sets its own rules and fees.
Scheme fee
The charge a card scheme levies on each transaction, separate from interchange. It is passed through to the merchant either as its own line or inside a blended rate.
Merchant account
The account an acquirer opens for a business to receive card payments. Funds pass through it before settlement to the business bank account. Pay-as-you-go providers bundle this into their service rather than opening one in your name.
Merchant ID (MID)
The unique number an acquirer assigns to a merchant account. It appears on statements and terminal receipts and is needed when querying transactions, handling chargebacks or switching provider.
Terminal ID (TID)
The unique number assigned to each individual card machine on a merchant account. A business with three terminals has one MID and three TIDs.
PDQ machine
The older UK name for a card machine, from "Process Data Quickly". The first PDQ machines, in 1979, read the magnetic stripe on a card; the term is still used for any physical terminal.
More on this →Chip and PIN
A card payment where the chip on the card is read by inserting it into the machine and the cardholder enters a four-digit PIN. The standard method for payments above the contactless limit.
Contactless
A card or mobile-wallet payment made by holding the card or device near the reader without inserting it or entering a PIN. Uses near-field communication (NFC).
Contactless limit
The maximum value of a single contactless card payment before a PIN is required. The FCA set the UK limit at £100 per transaction and £300 cumulative on 3 March 2021; since March 2026 card issuers with strong fraud controls may set their own limit, and £100 remains typical.
More on this →Card-not-present (CNP)
A transaction where the card is not physically presented to a machine: online, by phone or by payment link. Generally priced higher than an in-person (card-present) transaction and more exposed to chargebacks.
Payment gateway
The software that passes an online card payment from a website or app to the acquirer. Physical card machines do not need a separate gateway; online stores do.
SoftPOS / Tap to Pay
Software that turns a compatible phone into a contactless card reader with no extra hardware. Tap to Pay on iPhone is Apple's version; SumUp, Square, Zettle and Dojo all offer it in the UK.
More on this →Card reader
A small device that accepts card payments by pairing with an app on a phone or tablet, which supplies the screen and internet connection. Distinct from a terminal, which is self-contained.
More on this →Receipt printer
A thermal printer built into some terminals that prints a customer receipt, and on some devices the bill. Smaller readers and the Dojo Pocket send receipts by email or text instead.
More on this →EPOS (electronic point of sale)
The till system that records sales, stock and staff activity. A card machine can be integrated with an EPOS so the amount is sent to the terminal automatically, or stand alone with the amount keyed in by hand.
PCI DSS
The Payment Card Industry Data Security Standard, a set of security requirements for any business that handles card data. Most small merchants meet it by completing an annual self-assessment questionnaire.
PCI compliance fee
A monthly or annual charge some providers levy for PCI compliance administration, often with a separate higher non-compliance charge if the annual questionnaire is not completed.
Settlement
The transfer of card takings from the acquirer to the business bank account. Dojo's terms commit to transfer by the end of the business day after a transaction is processed, and no later than the third business day.
Chargeback
A reversal of a card payment initiated by the cardholder's bank after a dispute. The money is taken back from the merchant pending investigation, and providers usually charge a per-chargeback fee.
Rolling reserve
A percentage of card takings an acquirer holds back for a set period to cover potential chargebacks before releasing it. It reduces day-to-day cash receipts for as long as it applies.
Minimum monthly service charge (MMSC)
A floor on the fees a merchant pays each month. If transaction fees fall below it, the provider charges the difference, so quiet months still cost the minimum.
Terminal rental
A monthly charge for hire of the card machine under a contract, as opposed to buying the device outright. Sometimes a separate agreement from the card processing itself.
More on this →Minimum term
The initial period a card machine contract runs before it can be ended without an early exit fee. Under the Payment Systems Regulator's Specific Direction 16 the initial term is capped at 18 months for merchants with card turnover up to £10 million a year.
More on this →Rolling monthly contract
The arrangement a contract moves to after its minimum term, renewing one month at a time and ending on one month's notice from the merchant.
Early termination fee / early account closure fee
The charge for leaving a contract before the minimum term ends. SD16 requires such fees to be cost based, transparent and explained before the contract is entered into.
More on this →Trigger message
A notice a directed provider must send under Specific Direction 15, 31 calendar days before a minimum term ends and then monthly, stating the end date and linking to the provider's online quotation tool.
Summary box
A standardised one-page summary of a card-acquiring contract's prices and terms. Under Specific Direction 14, directed providers may not charge for a bespoke summary box or for use of their online quotation tool.
ISO (independent sales organisation)
A company that sells card machines and merchant services on behalf of an acquirer rather than processing payments itself. Terminal providers contracting through a directed acquirer are bound by the PSR's directions.
Payment Systems Regulator (PSR)
The UK regulator for payment systems. It issues the specific directions on card-acquiring contracts and enforces the Interchange Fee Regulation.
Headline rate
The percentage a provider advertises, usually for standard UK consumer cards in person. Premium, business and international cards and any fixed fees sit outside it.
Effective rate
Total monthly card fees divided by card turnover for the month. It captures every charge on the statement in one comparable number.
More on this →Mobile wallet
A phone or watch app such as Apple Pay or Google Pay that stores a card and pays by contactless. Authenticated on the device, so not bound by the card's contactless limit.
More on this →Common questions
What is the difference between an acquirer and a card machine provider?
The acquirer processes the payments and settles the money; the card machine provider supplies the terminal and may be the acquirer, a reseller for one, or an independent sales organisation. Your agreement is ultimately with the acquirer, and the acquirer's identity decides which regulatory directions apply to the contract.
What does PDQ stand for?
Process Data Quickly. It is the original UK name for a card machine, dating from the first magnetic-stripe terminals in 1979, and is still used for any physical card terminal.
What is the difference between blended and interchange++ pricing?
Blended pricing charges one percentage on every transaction with interchange, scheme fees and margin rolled together. Interchange++ itemises the three, so each transaction is priced on its actual card type and the provider's margin is visible as its own line.
What is a MID on a card machine?
The merchant ID, the unique number the acquirer assigns to your merchant account. It appears on statements and receipts and is the reference you need when querying a transaction, dealing with a chargeback or moving to a new provider.
Send us the statement and we will translate it
Send it over and we will translate each line into pounds and show a Dojo quote against it. Free, with no obligation either way.
CapExpand is an authorised Dojo partner and is paid by Dojo when a business signs up through us. That does not change the price you pay.
Sources
- Interchange Fee Regulation (retained EU 2015/751) and PSR: the IFR - 0.2% and 0.3% caps, in force 9 December 2015; checked August 2026
- FCA: contactless thresholds (3 March 2021) and FCA: flexibility on contactless limits (December 2025) - £100 / £300 limits and the March 2026 change; checked August 2026
- PSR Specific Direction 16, Specific Direction 15 and PSR news on SD14 - minimum terms, trigger messages, summary boxes; checked August 2026
- FCA Handbook PERG 15.3 - acquiring as a regulated payment service, terminal provision as a technical service; checked August 2026
- Dojo terms and conditions v1.6 - settlement timing (Section B condition 2); checked August 2026
- Mobile Transaction: What is a PDQ machine? - PDQ meaning and 1979 origin; checked August 2026