Hi all, can anyone advise me on a small problem I have? I have added a second external ADE Reson8 bellbox to my house alarm. The internal panel is an Optima Compact 8EP396A & this is connected to an external Vortex II bellbox. I have wired the second Reson8 as per the ADE wiring diagram for adding an extra bellbox. All works fine except for the fact the siren does not sound on the second bellbox when an alarm is actjvated. The strobe flashes on activation. Does this mean the Vortex II is not compatible & that I have to replace it with a Reson8? Any help would be much appreciated.