OutbufferSize

Sets or Retrieves the size of the Output (Transmit) buffers.

Available at Design time and Runtime. Read Only While the port is open.

MSComm32 and Comm32 have Similar but not identical behavior See Remarks below

Syntax object.OutbufferSize = value         object Name of the communications control.   value A numerical expression indicating the size of the transmit/output buffer.         Example object.OutbufferSize = 4096 '// Set the value             Text1.Text = object.OutbufferSize '// Retrieves the current size of the buffer

Remarks:

Set before the port is opened. This value takes effect (memory is allocated) when the port is opened.

If you write more data into the transmit buffer exceeeding the size of the buffer then data loss will occur without warning (an OnComm error event (not a runtime error) is triggered 'after' the data loss occurs) - Use larger buffers.

Differences in behavior between MSComm32 and Comm32

MSComm32
Maximum value is a (short) integer. (32k)

Comm32
Maximum Buffersize is a Long Integer.

Important: If removing MSComm32 from an existing project and replacing it with AxComm remember that MSComm32 limited this property to a 32k “Short” Integer value. If using larger buffers you will of course remember to use variables of a larger data type to receive/process return values etc.