The communication protocol encapsulating ReCon’s face recognition terminals provides interfaces for third-parties interested in integrated development. All face recognition terminals released to date are supported. Interface names, and incoming/outgoing parameters are self-explanatory as far as possible.
The interfaces provided by SDK are the equivalent of control in a program, and interaction with terminals can only be achieved by manually operated terminals.
At the same time, SDK also provides interfaces for some functions not available at the terminals e.g. automatic deletion of attendance records. These functions cannot be manually performed inside the terminal interface, but can be accessed via the Web management page.
The dynamic link library is based on ActiveX technology, and has strong adaptability in the Windows platform. It can be used with any languages using ActiveX, such as VB, VC, Delphi, C# and PowerBuilder.
The "interface call -> event return" procedure is used for most interfaces. This asynchronous mode ensures that third party programs using SDK do not freeze.
Encapsulation in the SDK communication protocol is realized in this manner. The parameters required by the protocol are entered in the form of interface parameters, and the result fields returned by the terminal are called back to the third party program as a response event in the event parameters.
3 SDK conventions
● The SDK interface itself provides a return value. This means that SDK receives a request from a third party, and the relevant terminal data can be retrieved from the corresponding event. The SDK interface return values are very important.
● When the event return in the requested command carries parameters such as feature data or photo data, judgment cannot be based merely on whether or not the strings in the feature/photo fields are empty, but instead should be based on the original length of the feature/photo instruction.
● Terminal time fields are restricted to between 1970-01-01 08:00:00 and 2038-01-19 11:14:07. Except where specifically stated that 0000-00-00 00:00:00 can be used to express a particular time, parameters in the time field should be values within this range.
●In parameters/fields where the event return is a string, judgment of validity cannot solely be based on whether the length of this string is non zero. Instead it should be based on the OP_CODE, or on the length of the return string, as SDK assigns the string “Unknown???” to unknown parameters/fields.”Unknown???”；
● User ID (0-10) is reserved for the system. User IDs used for relevant operations must be greater than or equal to 11.
● For operations on the same terminal, two interfaces with event returns cannot be called continuously, but must be called one after the other. Different terminals are not subjected to this restriction.
Test calls to the encapsulated interface functions can be made via the Demo provided by SDK. Terminal event returns received via the Demo make it easy to view the execution and response of terminals to the interface functions, making the Demo program an excellent guide for secondary development.