Security Advice · Ajax Alarms
Which Ajax Hub Do You Actually Need?
Detectors are cheap to change. The hub is not. It decides how many devices you can ever add, how far the system reaches, and whether an alarm gets out when the power and internet are both down.
The short answer
- The hub is the one component worth over-specifying. Adding a detector later is easy; outgrowing a control panel is not.
- The two things that matter most are device capacity and whether it has cellular failover.
- The Ajax Hub 2 Plus handles up to 200 devices, reaches up to 2,000m, carries 16 hours of battery and fails over to its own SIM.
- One hub can run wireless and Ajax Fibra wired systems wired detectors together, so you are not locked into one or the other.
The mistake this page exists to prevent
Nobody thinks about the hub. It goes in a cupboard and is never looked at again. That is exactly why it is the component people get wrong.
The expensive discovery is not made on install day. It is made two years later, when you want to add a sensor to the new sleepout and find the panel is full, or the far end of the property is out of range, or there is no way to get a signal out when the internet drops. At that point you are not adding a detector, you are replacing the system.
So the useful way to choose is not “what do I need today” but “what is the most this property will ever ask of it”.
The four things that actually differentiate a hub
1. How many devices it takes
This sets the ceiling on the whole system. The Hub 2 Plus supports up to 200 connected devices, which in practice means a house never runs out – you can add detectors, door contacts, smoke and flood sensors, sirens, keypads and a doorbell over years without approaching it.
2. How far it reaches
Ajax’s Jeweller radio protocol reaches up to 2,000 metres in open conditions. Real buildings are not open conditions, but the headroom is what lets a single hub cover a large section, a back shed or a sleepout without a second system.
3. What happens when the power goes
Up to 16 hours of internal battery. The system stays armed and keeps reporting through an outage rather than quietly leaving the property unprotected – which is what an alarm with no backup does, without telling anyone.
4. What happens when the internet goes
A built-in SIM that takes over automatically. This is the one people underestimate, because power and internet failures are correlated – a storm usually takes both. Covered in detail in do Ajax alarms work without WiFi or power.
What the hub connects to
Everything runs back to the same hub and shows up in the same app, which is the practical argument for a system rather than a collection of gadgets:
| Device type | What it covers |
|---|---|
| Motion & photo detectors | Including MotionCam, which photographs whatever triggered the alarm |
| Door & glass sensors | DoorProtect and GlassProtect on entry points and windows |
| Fire & flood | FireProtect and LeaksProtect – smoke, heat rise and water, in the same system |
| Sirens & keypads | HomeSiren, StreetSiren and KeyPad Plus for people who do not want to use a phone |
| Video doorbell | The Ajax DoorBell, with the hub as fallback if Wi-Fi drops |
| Wired devices | Fibra detectors alongside wireless ones on the same hub |
Sizing it to the property
- Apartment or small unit. You will never approach the capacity limits. What still matters is cellular failover, because an apartment’s internet is not yours to control.
- Standard family home. Capacity is comfortable. The real questions are range to the garage or sleepout, and whether you want photo verification on the detectors.
- Large section, outbuildings, rural. Range and battery headroom start to matter. This is where the 2,000m figure stops being a spec and starts being the reason it works.
- Commercial. Device count, per-user access and arming schedules drive the decision – see Ajax for business.
- New build or warehouse. Wired Ajax Fibra wired systems on the same hub, up to 100 detectors per line, no detector batteries to ever replace.
The one-line version: spend on the hub, then add detectors at whatever pace suits you.
That is the opposite of how most quotes are built, and it is why we quote itemised per device – so the hub decision is visible instead of buried in a total.
Common questions
How many devices can one Ajax hub handle?
The Hub 2 Plus supports up to 200 connected devices. For a home that is effectively unlimited – it means you can keep adding sensors, sirens, smoke detectors and a doorbell for years without hitting a ceiling.
What is the range of an Ajax hub?
Up to 2,000 metres in open conditions using the Jeweller radio protocol. Buildings reduce that, but the headroom is what allows sheds, sleepouts and large sections to stay on one system.
Do I need the Plus version?
It depends on the property and on what you want the system to do in an outage. The capabilities that matter most – device capacity, battery backup and automatic cellular failover – are the things to check against your site rather than the model name. We work that out on the site visit.
Can one hub run both wired and wireless detectors?
Yes. Ajax hubs run Fibra wired devices alongside wireless ones, so a site can have a wired backbone and still pick up a wireless sensor where cabling is impractical.
Where should the hub be installed?
Somewhere with good signal, access to power, and crucially not somewhere an intruder reaches first. Working that out is part of the site assessment – a hub mounted by the front door is a hub with a design flaw.
Can I add to the system later?
Yes, and it is the sensible way to do it. Cover the essential entry points now and add devices over time; nothing needs replacing to expand.
Get the hub decision right the first time
We look at range, signal, placement and what the property might ask for in five years – then quote it itemised, so you can see exactly what you are buying.