The Vanguard API Interface accommodates users of Vanguard Analyzers to access Vanguard device functionality without using the BusView GUI. It also allows the Vanguard API to incorporate Vanguard functionality in dedicated applications running on a wide-range of platforms and use a variety of programming languages.

The Vanguard API engine is implemented as a TCP/IP based server on the Vanguard device, using simple ASCII-formatted data for both requests and responses. The API is therefore accessible to every client platform that has basic TCP/IP support. The API engine integrates with the main Vanguard device firmware as follows:

The API engine integrates with the device firmware as a communications handler, in addition to the BusView Ethernet and USB communication handlers.

As with other Vanguard firmware, the API engine acts as a BusView emulator. This means simultaneous API and BusView connections are not possible and initialization overhead is needed each time an API client connects to the Vanguard API engine. When using the API, you should maintain the same TCP/IP connection throughout the API session.

Curtiss-Wright Controls API Interfaces for Clients
Two client interfaces are available for using the Vanguard API. The XML-RPC interface transmits the requests and responses as XML-formatted messages using HTTP. The Raw ASCII interface transmits RPC requests and responses as simple ASCII-coded strings and uses basic TCP/IP socket client/server communication for the transport.

The Vanguard API server selects the interface mode based on the incoming command data.

Raw ASCII interface - To use the Raw ASCII interface, a standard TCP/IP socket connection to the Vanguard API server needs to be established. Due to a certain API initialization overhead when creating a server connection, the client should keep the same connection open throughout the entire API session.

The Raw ASCII interface accepts requests as a set of ASCII strings, and returns data in a similar format. Each string should be terminated with a pair of carriage-return and line-feed ASCII characters (CR/LF pair).

XML-RPC Interface - XML-RPC is a Remote Procedure Calling (RPC) protocol which uses HTTP for the transport and XML for encoding. XML-RPC is designed to be simple, while allowing complex data structures to be transmitted, processed and returned. XML-RPC client libraries are freely available for a number of programming languages. (See www.xmlrpc.org for more XML-RPC specification.)

The Vanguard API XML-RPC server accepts API request parameters passed as a single XML-RPC array parameter or as individual XML-RPC parameters (strings, integers and booleans).