Ajax MultiTransmitter Installer Guide 2026
Updated 29 May 2026. The Ajax MultiTransmitter is the integration module UK installers reach for when a customer wants the Ajax app, push notifications and ARC signalling without ripping out an existing wired alarm. Eighteen wired zones, a mains-and-battery PSU, Jeweller radio back to a Hub 2 Plus and EN 50131 Grade 2 compliance — it is one SKU that turns a legacy wired PD 6662 system into a hybrid Ajax estate. This guide walks the trade-side decisions: when MultiTransmitter beats a like-for-like wireless retrofit, what it can and cannot take on its zones, the EOL wiring rules, Hub firmware gates, range planning and three reference bills of materials.
At a glance — Ajax MultiTransmitter, in one screen
- What it is: a wireless-to-wired bridge that adds 18 third-party wired alarm zones to an Ajax Hub via the Jeweller radio protocol.
- Pairs with: Hub Plus, Hub 2 (2G/4G), Hub 2 Plus (2G/4G), Superior Hub Hybrid (2G/4G) on OS Malevich 2.13 or higher.
- Zone types per input: NC, NO, EOL, 2EOL or 3EOL (2EOL/3EOL need MultiTransmitter firmware 2.13.0+).
- Cable run: up to 400 m per zone; three 10.5–15 V power outputs (1 fire + 2 device) with a 1 A total budget.
- Power: 100–240 V AC mains plus a 12 V backup battery (~33 mA average draw on battery, no detectors loaded).
- Radio: 868.0–868.6 MHz Jeweller, up to 2 000 m line-of-sight to the hub; two tampers; AES encryption.
- Standards: EN 50131 Grade 2 / PD 6662:2017 — covered when the wider Ajax system is set up per Ajax's PD 6662 article.
- Trade desk: stocked at our Leicester warehouse for same-day dispatch — 01163 800 838.
What is the Ajax MultiTransmitter?
The Ajax MultiTransmitter is a dedicated integration module that connects up to 18 third-party wired detectors to an Ajax wireless control panel over the Jeweller protocol. Each of the 18 inputs is configurable as a separate alarm zone with its own type, group assignment, response delay and notification rules inside the Ajax app — so a single MultiTransmitter behaves like 18 individually-named Ajax sensors as far as the Hub, the end customer and an ARC are concerned. Ajax positions it as the module for keeping legacy wired PIRs, smoke detectors, glass-break, magnetic contacts and panic buttons on a system being upgraded to Ajax wireless monitoring, app notifications and cloud services (ajax.systems).
When does MultiTransmitter beat a like-for-like wireless retrofit?
MultiTransmitter wins on three jobs: protecting existing wired infrastructure, controlling like-for-like replacement cost, and respecting site constraints where wireless is a poor fit. If a customer already has a 12 or 16 wired-zone Pyronix Enforcer system that is structurally fine but ageing on the user-experience side — no app, no ARC over IP, no push — fitting one Ajax Hub 2 Plus plus one MultiTransmitter onto the existing wired loops is usually faster and cheaper than swapping every PIR for an Ajax MotionProtect U or MotionProtect Plus U wireless detector. It also keeps cabling that has been tested, signed off and possibly fire-rated already in service.
The retrofit case strengthens further in two scenarios: heavy reinforced concrete or steel where Jeweller propagation is uncertain and a known-good 1.5 mm² cable run is more reliable; and listed or heritage buildings where surface-mounting wireless devices on visible walls is restricted and the existing wired sensors are already cosmetically hidden. On the flip side, if more than half of the existing wired sensors need replacing anyway, the wireless-everywhere route on a Hub 2 Plus with the Ajax wireless catalogue ends up cheaper per zone than buying MultiTransmitter plus 18 replacement wired heads.
Which Ajax hubs is MultiTransmitter compatible with?
MultiTransmitter is supported on Hub Plus, Hub 2 (2G), Hub 2 (4G), Hub 2 Plus (2G), Hub 2 Plus (4G), Superior Hub Hybrid (2G) and Superior Hub Hybrid (4G), provided the hub is running OS Malevich firmware 2.13 or higher. It is explicitly not compatible with the older ocBridge Plus and uartBridge integration modules, and it cannot be paired with third-party security control panels — it requires a current-generation Ajax hub at its head end (support.ajax.systems).
For most UK installs we ship one of three hubs alongside MultiTransmitter:
- Ajax Hub 2 Plus (2G) — the workhorse: 200 devices, Wi‑Fi + Ethernet + dual SIM 2G, photo verification with MotionCam.
- Ajax Hub 2 Plus 4G — same capacity with 4G+2G fallback; the default pick for sites without solid Ethernet.
- Ajax Hub 2 (2G) — 100-device, single-LAN, suits small commercial or domestic Grade 2 jobs.
If the customer wants a single panel-and-starter bundle to pair with MultiTransmitter later, Ajax StarterKit (Hub 2 + MotionProtect + DoorProtect + SpaceControl) is a common Grade 2 base; the larger Hub 2 Kit 3 and Hub 2 Plus DD-Kit 1 or DD-Kit 4 are the up-tiers when the customer wants photo verification or 4G+Ethernet+Wi‑Fi from day one.
What can each of the 18 zones take? (NC, NO, EOL, 2EOL, 3EOL)
Each of the 18 MultiTransmitter inputs is configurable from the Ajax app as one of five wiring topologies, matching what you would expect on a UK Grade 2 wired panel: Normally Closed, Normally Open, single end-of-line, double end-of-line and triple end-of-line. NC and NO suit basic detectors with no tamper return. EOL adds a tamper-detection resistor on the loop. 2EOL splits alarm and tamper. 3EOL splits alarm, tamper and fault on a single pair (ajax.systems specs). For installers used to Pyronix, Honeywell or Galaxy panels, the 2EOL and 3EOL behaviour is the same — pick the topology, set the resistor value in the app, run the cable.
To prevent guessing or substitution-attack sabotage, Ajax recommends using three different resistor values on a 3EOL loop in a ratio of R, 2R, 3R — for example 4.7 kΩ / 9.4 kΩ / 14.1 kΩ — so an attacker cannot bridge a single resistor and pass the loop test. 2EOL and 3EOL connections require MultiTransmitter firmware 2.13.0 or higher; older units must be updated via the Ajax app before they are deployed onto graded loops.
How far can a wired zone run from the module?
The maximum cable run between MultiTransmitter and a connected detector is 400 metres per zone, comfortably more than any typical alarm install needs. In practical UK commercial layouts that means one MultiTransmitter can serve a multi-floor office, a mid-sized retail unit or an entire small industrial estate from a single plant-room location, provided 1 mm² or 1.5 mm² alarm cable is used and tested for end-to-end loop resistance. The hub itself sits on Jeweller radio up to 2 000 m from MultiTransmitter in open ground, falling to "between several floors" indoors — Ajax's own guidance.
How is MultiTransmitter powered, and how long does it last on backup?
MultiTransmitter is fed from 100–240 V AC mains and carries an internal 12 V backup battery socket. Average current draw from the backup battery (with no detectors loaded) is around 33 mA, which gives roughly 60 hours on a typical 2 A·h pack before any detector load is added (ajax.systems specs). Real-world standby time falls with the number and class of detectors fed from MultiTransmitter's three onboard 10.5–15 V outputs — one dedicated to fire detection devices and two for general detectors and accessories.
Plan for it: the three outputs share a 1 A combined budget. A Grade 2 site with 12 PIRs at 12 mA each is comfortable; loading high-draw glass-break detectors, multi-LED sirens or external 4-wire smokes can push the total close to 1 A and erode standby runtime. When the load approaches the budget, either move sirens onto an Ajax wireless StreetSiren or feed external 12 V PSU(s) to the heavy loads and keep MultiTransmitter's outputs for low-draw zones.
Three reference site builds (UK installer-ready)
1. Domestic Grade 2 retrofit — Pyronix Enforcer to Ajax hybrid
Customer: a 4-bed detached with a 1990s-era wired Pyronix system, 8 PIRs, 4 door contacts, an internal sounder and an external bell box, all on 2EOL. They want the Ajax app, push notifications and IP-over-cloud ARC signalling without re-cabling the house.
| Slot | SKU | Qty | Notes |
|---|---|---|---|
| Control panel | Ajax Hub 2 Plus (2G) | 1 | Mains + battery + LAN + Wi‑Fi + dual SIM. Mount in loft. |
| Wired bridge | Ajax MultiTransmitter | 1 | Mounted next to the legacy panel. Re-terminate all 12 existing zones. |
| Wireless add-on | Ajax MotionProtect U | 2 | Garage + extension where no cable runs exist. |
| Reference panel (replaced) | Pyronix Enforcer V11 | — | Decommissioned; loops re-terminated into MultiTransmitter. |
2. Small retail — Grade 2 with photo verification
Customer: an independent jeweller with 4 wired PIRs and 2 magnetic shutter contacts already installed, who wants MotionCam photo verification on the till and back office added on, plus app and ARC.
| Slot | SKU | Qty | Notes |
|---|---|---|---|
| Control panel + IP | Ajax Hub 2 Plus 4G | 1 | 4G + Ethernet + Wi‑Fi for triple-path ARC. |
| Wired bridge | Ajax MultiTransmitter | 1 | Re-terminate 4 PIRs + 2 shutter contacts on 2EOL. |
| Photo verification | Ajax MotionCam U PhOD | 2 | Till and stockroom — On-Demand photo at alarm. |
| Bundle alt. | Hub 2 Plus DD-Kit 1 | — | Buy the Hub + starter wireless set as one SKU when starting fresh. |
3. Multi-building commercial estate — Grade 2 with outdoor perimeter
Customer: a light-industrial yard with a main office (8 wired PIRs and 4 contacts already in place), a separate workshop (no existing alarm), and an external perimeter to add.
| Slot | SKU | Qty | Notes |
|---|---|---|---|
| Control panel | Ajax Hub 2 Plus (2G) | 1 | 200-device capacity covers office + workshop + perimeter. |
| Wired bridge | Ajax MultiTransmitter | 1 | Re-terminate 12 office zones on 2EOL. |
| Workshop wireless | Ajax MotionProtect Plus U | 4 | Dual-tech (PIR + microwave) to suit metal workshop environment. |
| Outdoor perimeter | Ajax MotionProtect Outdoor | 2 | Yard sides — IP54, 50 m radio range. |
| Outdoor curtain | Ajax DualCurtain Outdoor | 1 | Two-sided 15 m curtain along the perimeter fence line. |
| Outdoor photo verification | MotionCam Outdoor / MotionCam Outdoor PhOD / HighMount PhOD | 2 | Pick by mount height — HighMount up to 9 m, others up to 3 m. |
How does MultiTransmitter sit in the Ajax PD 6662 picture?
MultiTransmitter is graded EN 50131 Grade 2 and is on Ajax's PD 6662:2017 compliance list. To bank that grading on a UK installation the wider Ajax system has to be configured per Ajax's own PD 6662 setup guide — that means a Grade-2-capable hub, the correct alarm transmission system (ATS) class, dual-path signalling where the ARC requires it, EN-class PSUs and Grade-2 detectors on the wired loops (Ajax PD 6662 guide). Sites that need Grade 3 cannot use the current MultiTransmitter Jeweller as a primary-tier detector bridge — Ajax's Superior MultiTransmitter Fibra (wired-backbone variant) is the Grade-3 path on the Hub Hybrid family.
How do I commission MultiTransmitter on a Hub 2 Plus?
Commissioning follows the same QR-code add flow as any Ajax device. Update the hub to OS Malevich 2.13 or higher, plug MultiTransmitter into mains, scan its QR code from the Ajax PRO app, terminate each wired zone, and configure the zone type (NC / NO / EOL / 2EOL / 3EOL), zone group and notification rules in the app. Test each zone with the connected detector triggered and confirm both alarm and tamper register in the event log. Drop a MotionCam photo verification add-on (MotionCam U PhOD) where the customer wants on-demand stills attached to alarms — they pair to the same hub independent of MultiTransmitter.
What does MultiTransmitter not cover?
Three honest gaps to plan around. First, it is a wired-input bridge — it does not give wired outputs back out, so wired sirens still need either an Ajax wireless siren equivalent or a separate relay module. Second, two-way wired devices (smart smokes that signal sounder status, addressable detectors, bus-based fire systems) are not in scope — MultiTransmitter is for conventional alarm loops. Third, MultiTransmitter does not extend Jeweller radio coverage; for that you need an Ajax ReX 2 range extender, which is a separate SKU.
Wired bridge or wireless replace — when does each win?
Use MultiTransmitter when more than half of the existing wired sensors are healthy, cable runs are tested, and the customer's pain is monitoring/UX rather than detector age. Use wireless-everywhere on Hub 2 Plus with the Ajax detector range when more than half need replacing anyway, when the site is timber-frame or single-floor (good for Jeweller propagation), or when the install window is short and re-terminating 18 wired zones into a MultiTransmitter is slower than dropping in 18 wireless detectors. For mixed cases, MultiTransmitter on the ground floor + wireless on the upper floors is a clean split and commonly the cheapest path.
How does MultiTransmitter compare with the Pyronix wired tier?
Pyronix's Enforcer V11 and its wired bus give a similar zone count with a self-contained panel and onboard keypad/prox, but no native phone-app push-with-photo and no MotionCam-style visual verification — those features live on Ajax. If the customer wants the Pyronix wired backbone with classical ARC-only signalling and a low monthly cost, Enforcer V11, ENF/KIT1-UK, ENF/KIT3-UK and ENF/KIT5-UK are the relevant Netview-stocked bundles. If the customer wants app + photo verification + cloud, MultiTransmitter on Hub 2 Plus is the upgrade path. See our full Ajax MotionProtect vs Pyronix KX guide for the indoor PIR side of the same comparison, and the Ajax StarterKit UK installer guide for the wireless-everywhere counterpart.
Frequently asked questions
Does MultiTransmitter work with the original Ajax Hub (non-Plus, non-2)?
No. The original first-generation Hub is not on the compatibility list. MultiTransmitter requires Hub Plus, Hub 2 (2G/4G), Hub 2 Plus (2G/4G) or Superior Hub Hybrid (2G/4G) running OS Malevich 2.13 or higher.
Can I run 2EOL on every zone without changing firmware?
Only if the MultiTransmitter is already on firmware 2.13.0 or higher. Older firmware supports NC, NO and single EOL only. Update through the Ajax PRO app before deploying onto graded loops.
What resistor values does Ajax recommend for 2EOL and 3EOL?
Ajax recommends three distinct values in the ratio R, 2R, 3R — e.g. 4.7 kΩ / 9.4 kΩ / 14.1 kΩ — to defeat substitution-attack sabotage. The value is set per zone in the Ajax app at commissioning.
Can MultiTransmitter feed wired fire detectors?
Yes. One of the three onboard 10.5–15 V power outputs is dedicated to fire detection devices, with the other two reserved for general detectors and accessories. Total combined load across the three outputs is capped at 1 A.
What is the maximum number of MultiTransmitters per hub?
That depends on the hub's overall device capacity — Hub 2 (100), Hub 2 Plus (200) — minus other devices already paired. Each MultiTransmitter takes one device slot regardless of how many of its 18 zones are populated.
Can MultiTransmitter signal to an ARC on its own?
No — it is a detector-side module, not a transmitter to the ARC. Signalling to the ARC happens through the Hub over IP/4G/2G per the hub's configured ATS path.
Buying and dispatch from Netview
We hold Ajax MultiTransmitter, Hub 2 Plus, Hub 2 Plus 4G, Hub 2, Hub 2 StarterKit and Hub 2 Kit 3 as stock SKUs in our Leicester warehouse for same-day UK trade dispatch. The wireless companion catalogue — MotionProtect U, MotionProtect Plus U, MotionCam U PhOD, MotionProtect Outdoor, DualCurtain Outdoor, MotionCam Outdoor, MotionCam Outdoor PhOD, HighMount PhOD — ships from the same shelves. Trade desk: 01163 800 838 · view all brands.
Last reviewed: 29 May 2026. Specifications and firmware gates verified against Ajax Systems product, manual and PD 6662 support pages on the day of publication. UK pricing, availability and dispatch lead times: contact the Netview trade desk.
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