The power sensor implements the 'Hypertext Transfer Protocol' (HTTP, RFC-1945) both, for the user interface and for the M&C interface. All communication, even setting operational parameters, is done with HTTP GET requests. For the user interface, the power sensor replies to requests with HTML pages which display the requested information in a web browser. For the M&C interface, the power sensor replies to requests with an one line text document.
Command parameters to the power sensor are appended as CGI form parameters to the URL (see RFC-1738). The first parameter always is 'fmt=txt' which tells the unit to reply a one line text document instead of a voluminous HTML page.