1. A method for providing a remote voice interface with a supervisory control and data acquisition system, the method comprising: by a human-machine interface telephone gateway, receiving from a cloud telephone service a text command identifying an element of the supervisory control and data acquisition system and an action to be performed, the text command being derived from an audio voice command received by the cloud telephone service from a human operator; transmitting, via an application interface with the supervisory control and data acquisition system, a system command based on the text command, after receiving a text approval in response to an approval request via a conference call; receiving, from the supervisory control and data acquisition system, a confirmation message in response to the system command; and transmitting, to the cloud telephone service, text for conversion to an audio message reporting the confirmation message to the human operator.
9. The method as claimed in claim 1 , wherein the supervisory control and data acquisition system is a system for monitoring and controlling an industrial process, and further wherein the system command is a command to remotely query a status of the industrial process.