We recommend up to 12 RF devices per system. The larger the system the more RF signals being transmitted and the greater the chance of signal clashing.  

This means there will be a lot of RF signals trying to transmit in a very tight time frame – as all the RF devices are interconnected, if a signal path is blocked by signal clashing, then the unit will not respond to a fire message.

As you noted, the RF devices form a mesh. 

Technically, 31 RF (radio) devices within a system is the max that is possible but ensuring that the signal gets to all 31 devices within the suitable time frame is very difficult to show and validate.

That said, quite a few of our Radio LINK systems installed have more than 12 x RF devices, and they work well.

However we always recommend the final configuration and set up is fully tested and verified – a button test on each device and a record that all other devices have responded to the message.

This can be slow and tedious process (not to mention loud), but is essential in proving that the system is working as designed.

Summary – We recommend up to 12 RF devices per system, if there are more be sure to fully test the system.

To answer your other question,  if all alarms sound and there is no obvious fire, how do you identify the alarm that initially triggered.

Pushing the hush button on one interconnected smoke alarm will silence all alarms except the one that activated, after the occupant confirms there is no fire, they can then push the hush button on the activating smoke alarm and it will be silenced.

However we would suggest installing a couple of Alarm Controllers into the system (ref EIB450), easiest way to explain how this works is to watch a factory video at the link below. We sell quite a large number of controller with RadioLINK systems as they allow the occupant to test and silence their alarms from floor level – no need to climb on a wobbly chair to reach the alarms.

http://www.youtube.com/watch?v=QxIc0QcFLyw