Output

Outputs/Sends data (Places bytes into the transmit buffer)

Not available at design time. Write only at runtime.

MSComm32 and Comm32 have similar but not identical behavior (See remarks below)

Syntax object.Output = value         object Name of the communications control.   value A String expression containing the characters/bytes to place into the transmit buffer.         Example.       object.Output = Text1.Text '// Places the contents of a text box '// into the transmit buffer.

Remarks:

See the the help section Sending Data for a more detailed explanation of the efficient transmission of data.

Ensure that your transmit buffer is large enough and has enough free space to hold the number of bytes. If you have a lot of data then you might consider splitting the data and repeatedly calling the Output property sending smaller amounts (Explained in the help section Sending Data as well as in the code samples)

Warning - If you attempt to insert too much data into the transmit buffer the data will be truncated. This property does not return an error - but an OnComm comEventTxFull is fired.

MSComm32
Under some circumstances (depending on the state of flow control and/or underlying comTimeOuts in the Windows com driver) calls to the Output property may not return quickly causing the application to appear to hang momentarily making the application feel a little unresponsive. (worst case scenario is that the application locks up for lengthy periods or even hangs forever) Under some flow control conditions the MSComm control may discard bytes/lose data.

Comm32
Comm32 uses overlapped I/O and double buffering isolating the application from the underlying com driver. Calls to the Output property return quickly and your application remains responsive.

The behavior of this function is also affected by the .OutputMode, .ParallelEnable and .TxTimeout properties.