handle in specifies an SMTP client handle that references system resources that LabVIEW uses to make SMTP requests. You can create an SMTP client handle using the Open Handle VI.

error in describes error conditions that occur before this node runs. This input provides standard error in functionality.

handle out returns an SMTP client handle that references system resources that LabVIEW uses to make SMTP requests. You can wire this output to the handle in input of other SMTP Email VIs. Use the Close Handle VI to dispose of the handle and free system resources when you no longer need the handle.

error out contains error information. This output provides standard error out functionality.