ISO/IEC 20060:2010 provides the specifications for the standard Open Terminal Architecture (OTA) kernel in several layers:
- definition of the virtual machine (VM);
- description of the services provided by the VM to terminal programmers;
- specification of a set of tokens representing the native machine language of the VM;
- specification of the format in which token modules are delivered to an OTA kernel for processing.
OTA defines a standard software kernel whose functions and programming interface are common across all terminal types. This kernel is based on a standard VM, which is implemented on each CPU type and which provides drivers for the terminal's I/O and all low-level CPU-specific logical and arithmetic functions. High-level libraries, terminal programs and payment applications may be developed using these standard kernel functions.