From the source code on the site:

/**
* Bandscope Receiver Applet 1.0.0
* @author Robert J Morton Email
* @version 13 March 2002
* @copyright Robert J Morton (all rights reserved) */

/* This applet conforms to API 1.1
Contains a method computePlots() that is specific to the way the
AOR AR8600 Communications Receiver provides bandscope data via
its RS232 port. This applet gets its bandscope data via data files
acquired via a web server from an RS232 port server with an AR8600
specific data handling method - all written entirely in Java. */

Walt