Yes, it played through the siren. Before this test, a DTMF code was sent to the siren that allows for live voice. When this happens, the siren will broadcast anything being transmitted from a certain radio frequency...this includes other siren commands which is what you heard here.
So from what I have observed… the last 2 digits in the model number indicates the number of modules/cells? Like, a Wps 2905 has 5 cells, a 2902 has 2 cells, and so on. Is this it? Or is it just a coincidence
*Clapping Intensifies* Good Job! Also in the next few months I will make the worlds first ########## Siren (Blocked for my safety :D). It might change the world one day.