There’s a particular kind of hardware that nobody writes case studies about. It doesn’t have a launch event. It isn’t on anyone’s wishlist. It gets bolted into a cabinet on a wet Tuesday, wired to a meter or a camera or a PLC, and then it’s forgotten about, which, if you think about it, is exactly what you want from it.
The Milesight UR35 is that kind of hardware. Over the last couple of years it’s become one of the routers UK integrators reach for by default when a site needs reliable cellular connectivity and there’s real equipment behind it. Not because it’s flashy, but because it quietly does the unglamorous things that separate an industrial router from a consumer 4G box. Here’s why it’s earned that reputation, and what to actually look for when you specify one.
The problem with treating 4G routers as a commodity
You can buy a 4G router for £40. It’ll even work, for a while, on your desk, with full signal, on a network that’s having a good day. The trouble starts when you put it somewhere that matters.
Industrial sites are hostile to connectivity in ways that catch people out. The cabinet gets to 55°C in July and below freezing in January. The signal is marginal because the enclosure is metal and the nearest mast is three fields away. The one network you chose has a regional outage the week after commissioning. And the thing you’re actually trying to connect, the meter, the RTU, the payment controller, doesn’t speak Ethernet at all; it speaks serial Modbus over an RS485 pair, and your cheap router has never heard of it.
An industrial router is built for all of that. The UR35 is a useful lens for understanding what “built for that” actually means, because it gets the fundamentals right without being over-engineered or overpriced.
Five things that make it industrial, not just labelled industrial
1. Dual SIM failover that you configure once and forget. The UR35 takes two SIMs, and if the primary network drops it switches to the secondary automatically. This sounds obvious until you’ve had a site go dark because the single network you trusted had a bad day. Put SIMs from two different carriers in and a regional outage stops being your problem. This is the single most valuable feature on any industrial router and it’s the one most often skipped on cheaper kit.
2. Real serial ports. One RS232 and one RS485, on a proper terminal block, running anywhere from 300 to 230400 bps. This is the difference between a router that carries internet traffic and a router that can actually talk to the industrial equipment on site. Most of the UK’s installed base of meters, loggers and controllers is serial. If your router can’t reach them, you’ve solved the wrong problem.
3. A protocol stack that understands the data. The UR35 works as a Modbus RTU-to-TCP gateway, so a serial PLC on the RS485 port is presented to your SCADA host as a clean Modbus TCP endpoint. No separate protocol converter. It’s also a native DLMS/COSEM client, which matters enormously in the current UK metering climate, and it speaks MQTT and SNMP for cloud and monitoring platforms. A router that just moves packets makes you buy a gateway. This one is the gateway.
4. A build that survives the field. IP30 metal enclosure, -40 to +70°C operating range, a wide 9 to 48 V DC power input with surge and reverse-polarity protection, and DIN rail mounting as standard. None of this shows up in a spec-sheet speed comparison, and all of it is why the router is still online in year three.
5. Isolated I/O and an on-device Python SDK. An isolated digital input and output let the router handle alarms and relay control directly, no separate controller. And because it runs Python on the device, you can make decisions at the edge, filter readings, trigger on thresholds, rather than shipping every data point to a server just to find out nothing happened.
Cat 4 LTE gives it up to 150 Mbps down and 50 Mbps up, with 3G and 2G fallback. That’s not a headline number, and it isn’t meant to be. Telemetry, SCADA, metering, CCTV and remote access don’t need more, and chasing raw speed at these sites is solving a problem you don’t have.
One router, four variants, a genuinely simple choice
The nice thing about the UR35 is that the range doesn’t make you agonise. There are four models, and they differ on exactly two things: Wi-Fi and PoE. The cellular modem, serial ports, I/O, protocols and VPN suite are identical across all four.
- UR35-L0GEU — the base unit. No Wi-Fi, no PoE. This is the serial-and-telemetry workhorse and the one most industrial jobs actually need. £151 ex VAT.
- UR35-L0GEU-W — adds 2.4 GHz Wi-Fi, for local on-site wireless or a Wi-Fi uplink path. £178 ex VAT.
- UR35-L0GEU-P — adds four PoE output ports. This is the one for remote 4G CCTV: it powers the camera and backhauls the footage from a single box. £163 ex VAT.
- UR35-L0GEU-P-W — both Wi-Fi and PoE, for sites that genuinely need everything. Built to order.
The decision is basically two yes/no questions. Do you need to power a device down the Ethernet cable? That’s PoE. Do you need to hand out local Wi-Fi or use Wi-Fi as an uplink? That’s the -W. Neither, and the base unit is your answer and your best value.
The one thing to get right at order time: Wi-Fi and PoE are factory hardware, not firmware options. You cannot upgrade a base unit later. GPS, if you need it, is a separate -G build that shares the Wi-Fi module slot. So specify carefully up front, or make a quick call to someone who does this daily rather than guessing.
Where the UR35 actually earns its keep
A few deployments where it’s become the obvious pick:
Smart metering. DLMS/COSEM support plus dual-SIM resilience makes it a natural fit for AMI and half-hourly settlement work, which is squarely relevant given where the UK metering programme is heading. The readings get home even when one network stumbles.
Water and wastewater SCADA. Remote pump stations and treatment sites with serial PLCs, backhauled over cellular, with isolated I/O for level and alarm signals, in an enclosure that copes with an unheated kiosk.
Remote and temporary CCTV. The -P variant powers an IP camera over PoE and provides its 4G backhaul from one unit. Ideal for construction compounds, car parks, events and rural monitoring where there’s no fixed line and no convenient mains.
Branch and unattended-site connectivity. Wired WAN primary with 4G failover, or 4G as the sole connection where a fixed line would take months to provision.
In all of them the same three strengths do the work: resilient connectivity, the ability to talk to real industrial kit, and a build that survives the field. That’s the whole job.
Don’t forget the SIM and the antenna
Two things quietly decide whether a cellular deployment works, and both are easy to get right.
The SIM matters more than people expect. A standard consumer SIM sits behind carrier NAT, so you can’t reach the router inbound for remote management or VPN. A fixed IP SIM fixes that. And for resilience, fit two carriers across the two slots. For multi-site rollouts, a multi-network IoT SIM that attaches to whichever network is strongest beats a single-carrier SIM every time.
The antenna is the other one. The UR35 ships with two cellular antennas, which are fine in good signal, but for cabinet installs or weak-signal locations an external or directional antenna is often the difference between a solid connection and one that drops overnight. Keep both antennas fitted to MAIN and AUX for the 2×2 MIMO the modem expects.
Both are worth buying alongside the router from the same place, so they arrive known to work together rather than being three separate gambles.
Where to buy it in the UK
The UR35 is stocked and supported in the UK by routerstore.com, the leading Milesight distributor in the country. That means genuine UK stock, next working day delivery on orders placed before 3pm, and, the part that actually matters, UK-based technical support from people who configure these routinely and know the four variants without looking them up. They also supply the IoT and fixed IP SIM cards and cellular antennas to complete the deployment, so you can buy the whole working install from one place.
If you’re not sure which variant fits your site, the phone is faster than the form. And since the wrong variant can’t be upgraded later, a two-minute call before you order is genuinely worth it.
This article was produced with technical input from the team at routerstore.com, the UK’s leading Milesight distributor. routerstore.com supplies industrial cellular routers, IoT and fixed IP SIM cards and cellular antennas, with UK stock, next working day delivery and expert UK-based support for engineers and integrators specifying connectivity for remote and industrial sites.