ECR Protocol


Cash register logs – The basis for modern payment systems

Introduction: What are cash register protocols and what are they used for?

In the world of cashless payment transactions, cash register protocols are essential for connecting cash register systems with payment terminals. They define how these devices communicate with each other and ensure secure and efficient payment processing.

Each cash register protocol has its own strengths, weaknesses and technical requirements. Some only work in local networks, while others are cloud-enabled. Likewise, some protocols require a numerical terminal ID to uniquely identify the terminal.

Advantages of a well-chosen cash register protocol:
Fast and reliable transactions
Easy integration into existing cash register systems
Greater security through standardized interfaces
Cloud connection possible for central administration

Here we present the most important cash register protocols with their properties, advantages and disadvantages.

Choosing the right POS protocol lays the foundation for stable processes and satisfied customers.

Overview of the most important cash register protocols



ZVT (payment terminal standard)

ZVT is the most widely used standard in German-speaking countries for communication between cash register systems and payment terminals. It is based on local network connections and requires a numerical terminal ID.

Cloud-capable? No, only local networks
Requires numerical terminal ID? ! Yes

Advantages:
Proven and widely used standard in Germany
High compatibility with many cash register systems
Stable and reliable performance

Disadvantages:
No cloud integration possible
Limited flexibility for modern, API-based systems
Not optimal for international markets



REST API

REST APIs enable modern communication between cash register and payment terminal via web interfaces. They are particularly flexible and often cloud-capable.

Cloud-capable? Yes
Requires numerical terminal ID? ! No

Advantages:
Platform-independent and flexible
Scalable for cloud and online systems
Ideal for modern cash register systems

Disadvantages:
Internet connection required
More complex implementation
Depending on provider's API availability



Cloud REST API

This variant of a REST API is completely cloud-based and enables central management of payment terminals via the Internet. No local infrastructure required

Cloud-capable? Yes
Requires numerical terminal ID? ! No

Advantages:
No local infrastructure required
Centrally controllable for chain stores
Scalable and flexible

Disadvantages:
Dependent on a stable internet connection
Observe data protection requirements
Possible latency due to cloud communication



O.P.I (Open Payment Interface)

The Open Payment Interface (O.P.I) is an interface for communication between cash register systems and payment terminals, which is used particularly in international markets.

Cloud-capable? No, only works in local networks
Requires numerical terminal ID? ! No

Advantages:
High security and stability
Supports various payment methods
Can be used internationally

Disadvantages:
No cloud connection possible
More complex integration than modern API solutions
Not as widespread as ZVT or REST API



ep2 (EFT/POS 2000)

ep2 is a payment standard developed in Switzerland that ensures consistent communication between POS systems and terminals. It requires a numeric terminal ID.

Cloud-capable? No, only local networks
Requires numerical terminal ID? ! No

Advantages:
Standard solution in Switzerland
High security standards
Consistent interface for various providers

Disadvantages:
Limited to the Swiss market
No cloud integration possible
Less flexible than modern API solutions



myPOS

myPOS is a modern cloud payment solution that does not require local infrastructure.

Cloud-capable? Yes
Requires numerical terminal ID? ! No

Advantages:
Easy to implement
Cloud-based for maximum flexibility
Supports many payment methods

Disadvantages:
Dependent on the myPOS provider
Limited customization options
Internet connection required



NEXO

NEXO is an internationally recognized standard for payment transactions that offers interoperability and security.

Cloud-capable? Yes
Requires numerical terminal ID? ! No

Advantages:
Future-proof and expandable
Internationally recognized
Supports cloud and local networks

Disadvantages:
Complex implementation
Not yet established everywhere
Higher training requirements



ISO 20022

A global payment standard that is particularly important for banks and financial service providers.

Cloud-capable? Yes
Requires numerical terminal ID? ! No

Advantages:
Future-proof standard
Supports many payment formats
High security

Disadvantages:
Complex and not always easy to implement
Higher customization costs
Primarily for banks, less so for retailers



SIX (TIM)

A proprietary protocol from SIX Payment Services, widely used in Switzerland.

Cloud-capable? No
Requires numerical terminal ID? ! No

Advantages:
High security
Specifically optimized for the Swiss market
Stable performance

Disadvantages:
Not internationally widespread
No cloud capability
Limited flexibility



Acquirer/SoftPOS provider's own POS protocol APIs

Many acquirers (payment processors) and SoftPOS providers (providers of software-based payment terminals) offer their own APIs for POS integration. These APIs are specifically tailored to their own payment systems and enable direct connection to the acquirer's platform or SoftPOS app.

Cloud-capable? Yes, in most cases
Requires numerical terminal ID? ! No, a unique merchant ID or API key is often used

Advantages:
Direct connection to the payment processor without a third party
Full control over payment processes
Often easy implementation thanks to modern API technology

Disadvantages:
Dependency on the respective acquirer or SoftPOS provider
Possibly less flexible than universal protocols
Different implementation requirements depending on the provider
Switching to another acquirer can require complex adjustments



Verifone FIPay / VX protocols

Verifone offers its own range of protocols for different terminal generations. These range from older VX models to modern Android-based devices with FIPay (Verifone's cloud-enabled API).

Cloud-enabled? Yes (FIPay) / No (older VX protocols)
Numeric terminal ID required? ! No

Advantages:
Widely used, especially in Europe and North America
Support for various payment types (credit card, NFC, mobile payment)
FIPay allows modern cloud integration

Disadvantages:
Proprietary protocol, therefore less flexible
Older VX protocols are not cloud-compatible
Partially limited to certain Verifone terminals



Adyen Terminal API

Adyen offers a completely API-based payment processing that can be combined with physical terminals, online payments and mobile POS solutions. Particularly interesting for international retailers with an omnichannel strategy.

Cloud-capable? Yes
Numeric terminal ID required? ! No

Advantages:
Very flexible API integration for POS, e-commerce and mobile
Supports contactless payments and digital wallets (Apple Pay, Google Pay)
No fixed terminal ID required

Disadvantages:
Strong focus on Adyen ecosystem - less compatible with third-party acquirers
Initial implementation can be more technically demanding
Adyen pricing models are not optimal for all retailers



Stripe Terminal API

Stripe is primarily known as an online payment provider, but also offers a POS solution with the Terminal API. Particularly interesting for startups, e-commerce companies and international merchants with cloud-enabled POS.

Cloud-capable? Yes
Numeric terminal ID required? ! No

Advantages:
Very easy API integration for POS and online payments
Scalable solution for merchants with multiple locations
Supports modern payment methods (e.g. Apple Pay, Google Pay)

Disadvantages:
Strong focus on Stripe ecosystem - less flexible for third-party providers
Not all acquirers are supported
Possibly higher transaction fees compared to traditional providers



CB2 (Cartes Bancaires - France)

CB2 is a widely used protocol in France for credit and debit card payments. It is used by most French banks and merchants and is closely linked to the Cartes Bancaires payment network.

Cloud-capable? No, only local networks
Numeric terminal ID required? ! Yes

Advantages:
Widely used in France
Direct connection to French banks
Optimized for national transactions

Disadvantages:
No native cloud support
Limited international use
Proprietary and strongly tied to France



J/XFS (Java/eXtensions for Financial Services)

J/XFS is an open standard for POS systems and ATMs. It enables the flexible connection of payment terminals, ATMs and other financial devices via a platform-independent API.

Cloud-capable? No (local integration)
Numeric terminal ID required? ! No

Advantages:
Standardized interface for various payment terminals
Good modularity for banks and large retailers
Independent of terminal manufacturers

Disadvantages:
Less common for classic cash register systems
Implementation can be complex
No native cloud support



ELM (Electronic Lock Management) - for gas stations & e-mobility

ELM is used for gas station and e-mobility payments. It connects cash register systems with gas pumps or charging stations to enable seamless payment processes. Specially developed for petrol stations and e-charging stations

Cloud-capable? Yes
Numeric terminal ID required? ! Yes

Advantages:
Specially developed for gas stations and e-charging stations
Cloud-enabled for modern mobility solutions
Supports various payment methods (card, app, RFID)

Disadvantages:
Very industry-specific - not suitable for traditional retailers
Implementation often only possible via specialized providers
Strong dependence on infrastructure providers



SoftPOS protocols (acquirer/provider-specific APIs)

SoftPOS solutions enable card terminal-free payment via smartphones or tablets. Many acquirers (e.g. myPOS, SumUp, Adyen, Stripe, PayPal) have developed their own API protocols for SoftPOS. No hardware required - a smartphone or tablet is sufficient

Cloud-capable? Yes
Numeric terminal ID required? ! No, a unique merchant ID or API key is often used

Advantages:
No hardware required - a smartphone or tablet is sufficient
Flexible and easy for small retailers or mobile service providers
Supports contactless payments (NFC, Apple Pay, Google Pay)

Disadvantages:
Often limited to certain acquirers or providers
Not all banks and acquirers support SoftPOS
Possibly higher fees per transaction



SumUp Terminal API

SumUp is a popular provider of mobile card payments and offers an interface for integration into cash register systems, mobile apps or online shops with the Terminal API. The API enables easy connection of SumUp terminals to POS systems and cloud platforms. Easy and quick integration via API

Cloud-capable? Yes
Numeric terminal ID required? ! No

Advantages:
Easy and quick integration via API
No numeric terminal ID required
Ideal for small merchants, self-employed and mobile service providers
Supports contactless payments and mobile wallets (Apple Pay, Google Pay)

Disadvantages:
Dependent on the SumUp ecosystem - less flexible for third-party providers
Limited customization options for larger merchants
Not all acquirers support direct connection to SumUp, e.g. no girocard acceptance
Possibly higher fees per transaction



Summary
The choice of the right cash register protocol depends on the individual requirements of a company. While ZVT and ep2 are proven, local standards, REST API and NEXO offer modern, cloud-enabled alternatives. Cloud REST API and myPOS enable easy cloud integration, while ISO 20022 is particularly relevant for banks.

The acquirer or SoftPOS's own APIs offer a direct connection to the respective payment platform and are particularly suitable for merchants who want to work closely with a specific payment service provider. Our recommendation

The right protocol not only allows payment systems to be integrated more quickly but also scaled securely.

💡 Our recommendation

If you are looking for maximum future security and flexibility, you should opt for an API-based or cloud-enabled solution.

If you need a proven, stable integration, you can use classic protocols such as ZVT or ep2.

If you already work closely with an acquirer or SoftPOS provider, you can benefit from their proprietary APIs.

Do you need a specific or unlisted cash register protocol? Feel free to contact us.

Let us advise you to find the optimal solution for your requirements!