Serial port buffering problems

Windows buffers serial input and output to COM ports independantly of Spectaculator.

Because of this, you may notice the sending computer may appear to transfer quite a lot of data before the receive command on the receiving computer is even entered.

Problems occur when the sending computer aborts a transfer before the receive command has been entered into the receiving computer:

• Windows may be buffering some of the sent data.

• Entering a receive command on the receiving computer will therefore result in that computer receiving some data even though the sending computer is no longer transmitting.

• This can be confusing initially if the another send command is issued on the sending computer. The receiving computer may receive some old data (from the aborted transfer) causing errors.

Spectaculator will attempt to purge all buffers on transmission errors as a precaution. However, sometimes it will be necessary to LOAD *"b" a few times on the receiving computer to clear the buffer.