This is an implementation of the ECR ZVT Protocoll used in payment terminals across Europe. It follows the ECR-Interface / ZVT - Protocol specification defined by the Verband der Terminal Hersteller e.V.. Currently, we follow Revision 13.11.
The specification can be downloaded here and the code, as well as the documentation references sections in this document.
The code also implements extensions defined by Feig, because this is the Terminal that Qwello uses in production in most of our charging stations.
The zvt_cli is both a useful swiss army knife to interacting with a payment terminal as well as the example on how you use the library.
A useful standalone tool is feig_update
which we use in production to update the Firmware of our cVEND plug terminals.
This will eventually also be folded into zvt_cli.