A payment terminal communicates with different target devices using different protocols. On the one hand, a distinction is made between the communication between the payment terminal and the control system within the machine. For this purpose, MDB, ZVT and O.P.I. established. On the other hand, the terminal communicates with one or more payment counterparts. This varies depending on the country and card system, but in general a distinction can be made between “multi-host” and “single-host” systems. In multi-host systems, the payment terminal communicates with several remote stations and payments are forwarded directly to the responsible credit card acqurier. In Germany, a “single host” system is usually used, in which the terminal only communicates with a single remote station, the network operator. Depending on the payment system, the data is only forwarded to the relevant credit card acqurier or headend of the German banking industry at the network operator.

ZVT Poseidon (DK)

ZVT Poseidon is the standard protocol for communication between payment terminals and network operators in Germany. FEIG TOPP terminals not only offer extensive support for this protocol, but also support the different "dialects" of the German network operators. For common network operators, FEIG offers fully certified payment applications; other network operators can be integrated quickly and easily.


NEXO ( is a new, ISO20022 certified standard for the payment industry. It is a complete protocol suite that sets standards for communication between terminal and acquirer as well as for other payment applications such as terminal management or communication between machine / cash register and payment system. FEIG already supports customers in the implementation of the NEXO standard in development and pilot projects.


EPS (Electronic Payment Systems) is one of the most important standards in the vending industry. It comes from the European Vending Association (EVA) and describes technical specifications for the integration of cashless payment systems in machines. The cut-out and the attachment of the terminal are specified, as well as the electrical connection and communication via MDB. FEIG cVEND box and box + machine modules support the EVA EPS standard and can be installed quickly and easily in the specified cut-outs. The best MDB interface on the market ensures that FEIG terminals can be operated in almost all existing vending machines.

Protocols ZVT – MDB – O.P.I.

ZVT, MDB and O.P.I. are frequently used protocols for communication between payment terminal and machine control. This differs depending on the industry and application. FEIG terminals always receive all available protocols. For many years, MDB has established itself in the vending industry as a standardized connector, for power supply and as a transmission protocol. All other payment systems, e.g. coin changers or bill readers, are also connected via MDB. As an alternative or in addition to existing systems, FEIG terminals can be easily integrated without changing the machine software. With the best MDB interface on the market, almost all existing machines can be retrofitted without any problems. In other industries such as parking, public transport or EV charging, the ZVT host protocol, which comes from the trade, has established itself. Here, too, FEIG offers full support of the protocol and functions such as configuration, diagnosis and updates can be carried out via ZVT.

The older O.P.I. Protocol is only used in some areas such as petrol stations. FEIG continues to offer full support for this protocol.

By the way: With FEIG terminals (software) protocols are independent of the interface used. For example, the ZVT can be used either via a serial interface (RS232), USB or via LAN. In the case of LAN, there is even no direct cable connection between the controller and the payment terminal and the terminal communicates via a connection with both the machine controller and the network operator / payment service provider.

Hightech - Made in Germany

FEIG ELECTRONIC has been a development partner and specialist in contactless identification (RFID), control electronics, traffic sensors and payment terminals for more than 50 years. From our headquarters in Weilburg, Germany, the ca. 400 people who work for us contribute to technological progress by developing innovative solutions for a wide range of applications and industries.

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