False alarms with DSC wireless keyfob

I have had a few unexplained panics from DSC WS4939 key fobs. In a couple cases I suspect they were caused by accidentally pushing on the button. But in two separate cases, customers insist they were nowhere near the units when it happened. These were new units though, and neither showed a low battery.

Conversely, I replaced a low battery on a very old 900MHz key fob about 3 months ago, but never had a false panic there.

I hope I'm wrong on this but what version wireless receiver is on it?

I know what you're thinking, but there was no mention of panics with that receiver.

I don't use DSC but here's my take on things of this sort.

Every great once in awhile, a transmitter will go into an alarm condition for no discernable reason. Changing the battery stops it. Here's what I think may be happening. Lithium batteries are used because they maintain their value for a long period of time. That is, they don't gradually drop of in voltage output over time. However when they get to the end of their life, they drop off rapidly. I think that somtimes a lithium does drop to a lower voltage output and hangs there and/or when it come time for it's polling signal or battery status signal to be sent, a *defective* battery could drop considerably in voltage causing the polling or status transmission to be mis- transmitted as an alarm condition. It's just a theory, but changing the battery has worked for me. However, there are times when it will occur again. Then, of course it's time to change the transmitter.

If I'm called in for a service call, I don't mess around with changing the battery ..... I just change out the unit. If the customer wants to play around with it himself, he may want to try the battery exchange before paying for a service call and new unit .... (if out of warrantee) So I'll put that particular zone on hold for a period of time until he's satisfied it worked or needs a service call.

RHC: Your logic sounds OK. I suppose it could just as easily be this as well as anything else. I've found over the years that a lot of alarm equipment on the market has "quirks" or "bugs" in it that sometimes makes it do totally unexplainable things from time to time. It seems to be more prevalent in wireless devices, but regardless, it can drive you bananas trying to diagnose exactly what the problem is, and how to solve it. I hate "solving" a problem but not actually knowing why it did what it did; there's no way to know if you have actually fixed it long term.

For the moment, I have deactivated the suspect device until he gets another battery for it, or has me do a service call to fix it.

Thanks

"This is to inform you of an issue regarding the PC5132-433 v4.2 wireless receiver. Over time, the PowerSeries control panel will display an incorrect wireless key low battery trouble. The issue is caused by leaving unused wireless keys programmed with serial number [000000]. Please note that if the issue occurs, panel operation will not be affected in any way."

So what does that have to do with a phantom panic signal??

I've been dealing with wireless for a long time and yes it is quirky. But afterwhile you sort of know what they are and just deal with it. If I were an injuneear I'd probably want to know what the specifics were, bad enough to persue it. But ......... in our business we have to deal with the symptoms. If we can cure the problem .... the most expedient way is the best way. Actually knowing the nity grity of what causes these quirks is not worth the time finding out the actual why...... cause they don't happen that often and there's nothing you can do to anticipate a "quirk" (if you will). It's when the problems recur that you have to get on it and see if it's a product defect or whatever.