I have a request from one of my clients to interface a USB cash drawer to my application. In most retail applications, the cash drawer is attached to a receipt printer that includes a port (interface) to plug the drawer into. The driver for the printer includes escape codes to open and release the drawer. My application does not use a receipt printer so I will be forced to use a drawer with a USB interface. Unfortunately, there are no drivers for USB cash drawers. However, they do have a DLL that will allow you to pass commands to the drawer.
Questions: 1) Has anyone interfaced a USB cash drawer to their RBASE application? If so, details please. 2) The manufacture of the cash drawer supplies a DLL which I have copied a portion and inserted below. I read through Mike's 2008 conference presentation on "Understanding DLCALL" but I am unclear on how to construct the commands to make the drawer open. I do not have the drawer yet, because I do not want to make the purchase until I am confident that I can make RBASE pass the commands. Please supply your opinions if you have used DLL call to communicate with RBASE. 1. GetDrawerHandle This function determines if the cash drawer controller has been added to the bus. If so it returns the valid handle to the controller, else it return a 0. C Calling Structure: ULONG GetDrawerHandle(BYTE drawer_number); example: handle = GetDrawerHandle(0); if (handle) drawer_online = TRUE; else drawer_online = FALSE; Visual Basic Calling Structure: Private Declare Function GetDrawerHandle Lib "MSPOS_USB.dll" (ByVal Handle As Long) As Integer example: Handle = GetDrawerHandle(0) If Handle > 0 Then Drawer_Online = TRUE Else Drawer_Online = FALSE End If 2. GetDrawerStatus This function returns the state of the switch on the controller. You must give the function the handle to the cash drawer you are using. The function will return failure [0], drawer closed [1], or drawer open [2]. Note: The DIP-SWITCH position four controls whether the system responds to a NO [0] or a NC [1] switch. C Calling Structure: int GetDrawerStatus(ULONG device_handle); example: result = GetDrawerStatus(handle); if (result == 2) drawer_open = TRUE; else if (result == 1) drawer_open = FALSE; else drawer_online = FALSE; Visual Basic Calling Structure: Private Declare Function GetDrawerStatus Lib "MSPOS_USB.dll" (ByVal Handle As Long) As Integer example: Result = GetDrawerStatus(Handle) If Result = 2 Then Drawer_Open = TRUE ElseIf Result = 1 Drawer_Open = FALSE Else Drawer_Online = FALSE End If 3. OpenDrawer This function opens the cash drawer. You must give the function the handle to the cash drawer you are using. The function will success drawer opened [2], drawer already opened [3], or failure [0]. The solenoid will fire ONLY if the drawer is closed. C Calling Structure: int OpenDrawer(ULONG device_handle); example: result = OpenDrawer (handle); if (!result) drawer_online = 0; Visual Basic Calling Structure: Private Declare Function OpenDrawer Lib "MSPOS_USB.dll " (ByVal Handle As Long) As Integer example: Result = OpenDrawer(Handle) If Result = 0 Then Drawer_Online = FALSE 4. ReleaseDrawerHandle This function will release the device handle. Call this function when your program is finished using the device or when your program exits. C Calling Structure: int ReleaseDrawerHandle(ULONG device_handle); example: result = ReleaseDrawerHandle (handle); Visual Basic Calling Structure: Private Declare Function ReleaseDrawerHandle Lib "MSPOS_USB.dll " (ByVal Handle As Long) As Integer example: Result = ReleaseDrawerHandle(Handle) John
