The ATE Systems Calibration Library is a set of programming libraries which expose functions that allow an RF/microwave system to be calibrated using a Keysight PNA and ATE System's devices. The libraries provide an application programming interface (API) that can be used in native WIN32 / "C" applications (such as LabView CVI) or applications based on Microsoft's .NET framework languages (such as C# and VB). For native C programs a header file "api.h" is provided and for .NET an interface named IApi is provided. Both APIs provide the exact same functionality with adjustments for language frameworks.

The calibration library utilizes ATE system's devices and a Keysight PNA. All communication with component hardware (see System Components) is achieved through a SCPI command interface over a TCP/IP LAN network. This communication can be logged, read by humans, and is very simple and easy to understand. A utility is provided that allows one to execute defined calibrations and see the log of commands being exchanged. ATE System's devices extend the SCPI standard so that every command received is acknowledged or returns data.

While the library provides functions to communicate and control individual devices for programmers that wish to control and program every aspect of a calibration process, the heart and major utility of the libraries lies in the execution of predefined calibrations that are defined by a configuration file. The libraries themselves have a very simple API, the complexity lies in the configuration of devices, calibrations and sequences. Configuration is achieved using an "INI" format configuration file that is easy to read, understand and modify. Configuration files can be edited using any standard editor, and no programming skill is necessary to setup or modify calibrations.