This is a hardware limitation. To support visual alarm verification, Hub 2 is equipped with two radio modules. The first module uses the Jeweller radio protocol, which is responsible for communication between the hub and Ajax security devices, as well as for prompt delivery of alarms. The second radio module is reserved for the new Wings radio protocol, transmitting images of MotionCam motion detector.
No more than 10 sirens HomeSiren or StreetSiren can be connected to the hub!