They do have SDK. Now they send me a sample in VB :
Their sample goes like this :
Sub test()
Dim MyRequest As PaymentAppCOM.TransactionRequest
Set MyRequest = New TransactionRequest
MyRequest.Device_Set_2 "PAX_SP30", "192.168.0.155", "10009"
MyRequest.xKey = "xTest_My_Grocery"
MyRequest.xVersion = "4.5.3"
MyRequest.xSoftwareName = "My_Grocery"
MyRequest.xSoftwareVersion = "1.0"
MyRequest.xCommand = "cc:sale"
MyRequest.xAmount = 1.23
Dim MyResponse As TransactionResponse
Set MyResponse = MyRequest.Manual(False, False, True, True, False, False, False, True, Nothing)
MsgBox MyResponse.xResult
End Sub
I get suggestion to use hb_LibLoad and hb_DynCall but I have no idea how to set all the variables.