I/O ActiveX Control Guidelines
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  1. The Open function can fail on NT if another device is setup to use the port that is trying to be opened. Remove other drivers/devices from the port you are trying to open, including printer drivers and network re-directs.
  2. When reading a parallel port's status the I/O ActiveX control will use the RS1284 protocol to read the data from the port.
  3. The recommended serial cable is a "Null modem" cable.
  4. You can connect two PCs together with a serial cable and send data to/from the connected PCs. Connect the PCs and run the IODemo on both PCs and select the correct ports and do reads and writes. You can run a terminal program on one PC in place of the IODemo.
  5. How often status is monitored before an event is fired is controlled by the property StatusEventInterval. The default value is 250 milliseconds. Making this value smaller makes status events more sensitive to a change. A value of 0 disables the status events.
  6. ParallelStatus can fail on Win NT if there is a printer driver setup to use the parallel port that I/O is being done on. Remove other drivers/devices from the port you are trying to use, including printer drivers.
  7. For a more responsive user interface during I/O, consider using the Background mode of operation. Set the Mode property to MODE_ASYNC (2).
  8. During application shutdown errors can occur. To address this issue, ensure no calls to the I/O object are made after the I/O object is destroyed. To do this, move the I/O object shutdown processing to be done before the application shutdown processing is done. Note: It is recommended that "IO.Close()" is called before an application begins to shut down.
  9. To clear the input and output buffers, Call the "IO.Close()" function and then reopen the port via the "IO.Open()" function.
  10. Events are fired from the primary thread. If an event does not fire, call the IO.Wait() function with a value of 100 to 1000.
  11. On Win NT, the parallel port does may not accept timeouts. To avoid a dead lock, check the port status (ParallelStatus) before doing I/O on a parallel port on Win NT.
  12. Note: On PC's setup for countries such as Chinese, Japanese, or other symbol type languages, you may have to use the ReadBytes() and WriteBytes() functions to avoid unwanted Unicode character translation.


Using the purchased copy:

You should ensure that only one copy of the "IO.OCX" is on your development machine. You may have to re-insert the I/O Control onto the form you are using it with. Then re-compile your application.

NOTE: if you test deploy your application on your development machine, you may end up with more than one copy of "IO.OCX" on your machine. Delete the "IO.OCX" files and re-install the I/O Control for further development.

Redistribution of files:

1) You will need to redistribute "IO.OCX" with the application that you write.
2) "IO.OCX" may need to be registered with the OS when it is distributed.
a) If you distribute with "InstallShield(R) Express 2" the IO.OCX will self register.
b) If you distribute with Visual Basic setup utility the IO.OCX will self register.
c) Other method: run "Regsvr32.exe IO.OCX".
Files you may need to redistribute/install:

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