procedure SendBreak(mSecs : DWORD; Yield : Boolean);
Transmits a break signal.
This method transmits a break signal (the transmit line is held in the "marking" state) for the number of milliseconds specified by mSecs.
When Yield is True, SendBreak yields control back to the operating system while sending the break, giving other applications and other parts of this application a chance to run. When Yield is False, SendBreak does not yield.