Queries or sets the software handshake (automatic XON/XOFF)

Syntax COM_SOFT(<nComPort>,[<lNewHandshake>],[<cXONchar>], [<cXOFFchar>]) --> lOldHandshake Arguments <nComPort> Designates the port (1 to N) for which the software handshake is set. <lNewHandshake> Designates whether the handshake is on (.T.) or off (.F.). If this parameter is omitted, the function returns the current setting. <cXONchar> Designates any character you choose as an XON character. The default character is ASCII 19 - Ctrl-S. <cXOFFchar> Designates any character you choose as an XOFF character. The default value is ASCII 17 - Ctrl-Q. Returns The function returns the previously set value. Description With modem connections, a hardware handshake is impossible, which is why we are making a software handshake available with this function. When a buffer is 75% full, an XOFF character (Ctrl-Q) is transmitted to the remote station. As soon as the buffer has again been emptied to 50% or less, the XON character (Ctrl-S) is transmitted. You can use characters other than Ctrl-S or Ctrl-Q for individual protocols, which would then be taken into account in the situations described above. Notes The software handshake only supports background transmission (when COM_OPEN() has been implemented with the third parameter <nBufferOut>). When you want to transmit binary data, the software handshake must always be turned off. Example COM_OPEN(1, 1000, 1000) // Open port, background transmission COM_SOFT(1, .T.) // Software handshake COM1

See Also: COM_HARD()