Yale HSA3800 : Signal box pluged in?

Please bear with me on this - I have no experience of wireless alarms and have moved into a house with one.

Read on here that the signal box could sometimes be plugged in, in the room behind?

My alarm unit is plugged in (via adaptor) but why would the signal box be plugged in if it's wireless (sorry if stupid question). Can it run from the mains with a battery backup (again, understand the signal box has batteries in).

I have a huge amount of wires going through a fitted wardrobe in the bedroom (signal box on outside wal) and recon one could be from the alarm box?

Sorry for this, I'm just trying to understand the sort of system and how it works. I'm used to a bog standard wired in alarm, none of this wireless malarkly and batteries.

CookEe01 said:

why would the signal box be plugged in if it's wireless (sorry if stupid question).

Click to expand...

Not a stupid question. It is one people should ask more often.

Siren boxes that are totally wireless have to rely on batteries for their power to make a loud noise when necessary. If the batteries go flat then the box cannot make an alarm sound. Even worse some systems cannot even tell the owner / user that the battery is flat.

To get round this serious problem some boxes use wireless communications for the alarm and control signals but have a wired connection to a power unit inside the building. This is simply a hole in the wall and a plug in power unit in the power socket nearest to the hole.

The yale hsa3800 does not have an adaptor powering it's siren from the mains so either the wiring and plug does not relate to the siren or the previous owner has made an adaptation of his own. (Not a difficult task)


Have today been to three previous clients and replaced all their batteries. No system issues at all - new batteries = systems working perfectly again.

Keep the batteries up to date by replacing them every two years and you won't have any probs