[RFI] Smoke-alarm Interference - not TVI but SAI

[Jim Brown]

On 10/22/2014 7:47 AM, Mike Ryan wrote:
> ANY amount of HF rf would set it off. 

The alarm industry is notorious for ignoring RF susceptibility. When the 
RF is coupling via wiring from dry contacts in the form of a simple 
on/off, a cap across the input of the receiver will generally fix it. If 
the interconnect is sending data, a cap will likely kill the data. Mfrs 
often tell their users to use parallel conductor wiring for 
interconnects, which makes them more susceptible to differential mode 
RFI. They SHOULD be using good twisted pair, which strongly rejects 
differential mode coupling.

73, Jim K9YC