I watched the live webinar. The siren plugging into the 4200 has been in the works for awhile now. It was suppose to be a feature when they first released the Storm Pro 100W. It looks like they will have it for the newer version of the Storm Pro 100W, which is what is in the video. The 4200 will also have, at the very least, a new software for the interface. If you notice in the video also the 100W siren doesn't have the 4 outputs set. Instead you can choose which tone is on what output and the outputs have priorities, so output 2 will override 1, 3 overrides 1&2, and 4 overrides 1-3.