Most cellular gateways come in a box. You mount the box, cable it, power it, and then design your enclosure around it. For a one-off installation that is fine. For a manufacturer trying to build cellular connectivity into their own product, it is wasted space, wasted cost, and a mechanical problem to solve.
The Teltonika Oxa takes a different approach. It belongs to Teltonika’s embedded systems line rather than the boxed router range, and its datasheet lists no casing material at all. The Oxa is built to sit inside host equipment. At 70 by 18.2 by 67.7 mm and just 36 grams, it is small enough to fit inside a gate barrier, an EV charger, a vending machine, or an access control panel.
What makes it worth writing about is not only the size. The Oxa runs RutOS, Teltonika’s OpenWrt-based operating system. That means the same networking stack, industrial protocols, VPN suite, and security features you find across the RUT and TRB ranges, on a board you can design into your own product. This is the difference between an embedded gateway and a bare cellular module. With a module you are still writing and certifying firmware. With the Oxa, that work is already done.
The specification, in brief
| Group | Detail |
|---|---|
| Cellular | 4G LTE Cat 4, up to 150 Mbps down / 50 Mbps up. 3G and 2G fallback. 3GPP Release 11 |
| SIM | 1 x Mini SIM (2FF). Single SIM |
| Ethernet | 1 x RJ45, 10/100/1000 Mbps Gigabit |
| Processing | ARM Cortex-A7 1.3 GHz, 128 MB DDR2 RAM, 512 MB flash |
| Operating system | RutOS (OpenWrt-based Linux), with SDK and Package Manager |
| Industrial protocols | Modbus TCP, DNP3, DLMS/COSEM, BACnet/IP router, OPC UA, Data to Server. All IP-based, no serial ports |
| VPN | OpenVPN, IPsec, WireGuard, GRE, L2TP, DMVPN, ZeroTier and more |
| Cloud and management | Teltonika RMS, TR-069, Azure IoT Hub, AWS IoT Core, ThingWorx, Cumulocity |
| I/O | 1 x digital input, 1 x digital output, with I/O juggler event logic |
| Antenna | 1 x SMA for mobile |
| Power | 4-pin DC, 9 to 30 VDC, reverse polarity and surge protection. Passive PoE via LAN1. Under 5 W |
| Environment | -40 °C to 75 °C operating temperature |
| Size and weight | 70 x 18.2 x 67.7 mm, 36 g |
Two limitations are worth stating up front, because they decide whether the Oxa is right for a given job. It is single SIM, so there is no second SIM for automatic failover. And it has no RS232 or RS485, so every industrial protocol runs over TCP. If your application needs serial equipment or dual-SIM redundancy, a serial-equipped gateway is the better choice. If it needs a small, embeddable Cat 4 board with a Gigabit port, the Oxa fits.
Why an embeddable board makes commercial sense
The value of the Oxa becomes obvious once you have costed a real embedded project. Building connectivity from a bare cellular module means designing the RF layout, integrating the modem, writing and certifying the firmware, and carrying the regulatory approvals yourself. That is months of engineering and plenty of opportunity for field failures.
Starting from a boxed gateway instead means paying for a housing you then have to squeeze inside your own enclosure, along with mounting hardware you do not need. Neither is efficient for volume manufacturing.
The Oxa sits between the two. You get a production-ready, pre-certified cellular platform with proven firmware, in a footprint you can lay out inside your own product. Cat 4 is the sensible modem tier for this class of device: cheap, globally supported, and low power. Its 150 Mbps ceiling is far more than embedded telemetry, control, or verification traffic will ever need, and real-world speeds of 60 to 80 Mbps on a strong cell leave ample headroom. Under 5 W of draw and a wide -40 to 75 °C range mean it copes with sealed and outdoor enclosures without special provision. It does need an external antenna on its SMA connector, and antenna choice matters more than most people assume. There is a fuller discussion of that on iotantenna.co.uk.
Where the Oxa fits
The combination of a compact embeddable board, Gigabit Ethernet, digital I/O, and a full set of TCP industrial protocols suits a wide spread of applications.
Access control at gates and barriers
This is the application Teltonika launched the Oxa alongside, and it is a natural fit. Modern access points verify an NFC card, a mobile credential, or a ticket in real time. The hard part is rarely the reader. It is the connectivity. Trenching fibre to a perimeter gate or a barrier in the middle of a car park is slow and expensive. Embedding the Oxa inside the controller lets the credential be checked against a cloud database over LTE and the unlock response returned in milliseconds, with no ground works at all. Because it runs RutOS, that traffic travels inside an encrypted tunnel behind the firewall.
EV charging
Charge point operators need every unit online for OCPP back-office communication, remote updates, and payment authorisation. The Oxa gives each charger its own cellular backhaul managed through RMS, with the digital input available for enclosure tamper detection.
Vending, kiosks, and unattended retail
Cashless payment, stock reporting, and telemetry all depend on a connection inside a machine with no wired network nearby. The Oxa slots into the cabinet and keeps the payment terminal online over a secure tunnel.
Building automation
The built-in BACnet/IP router makes the Oxa useful where a remote plant room or outbuilding needs to join a building management system over cellular rather than structured cabling. OPC UA support extends the same reach to modern automation controllers.
Smart metering
DLMS/COSEM client support over TCP is designed for utility meter data exchange. For sub-metering across a site, or collecting readings from a location with no fixed line, the Oxa becomes the cellular collection point feeding a head-end system.
Solar and renewable monitoring
Inverters and site controllers that expose Modbus TCP can be polled directly and forwarded to a monitoring platform. Note the IP-only limit: an inverter offering only Modbus RTU over RS485 will need an external serial converter or a serial-equipped gateway.
Machine builders and OEMs
Any equipment manufacturer who wants to ship a connected product without developing connectivity in-house can design the Oxa in. RutOS handles the networking, RMS handles the fleet, and the digital I/O gives a simple hook for machine status, alarms, or a remote reset.
Managing a fleet with RMS
A spread of embedded gateways is only workable if you can see and update every unit remotely. Every Oxa is compatible with the Teltonika Remote Management System, so an operator running dozens or hundreds of connected devices gets a single view of the whole estate. Through RMS you can monitor connectivity, push configuration changes, roll out firmware, and troubleshoot individual units without a site visit. For access control, EV charging, or metering across many sites, removing the truck roll is often what makes a deployment scale.
One practical point on connectivity: a single-SIM device is only as reliable as the SIM inside it. For estates that span regions or need consistent coverage across networks, a multi-network roaming SIM is usually a better fit than a single-operator consumer SIM. There is more on choosing IoT SIMs at roamingsims.co.uk.
The verdict
The Oxa is a focused product. It does not try to be a serial gateway or a dual-SIM router, and it is better for it. What it offers is a small, low-power, embeddable Cat 4 board with a Gigabit port, the full RutOS software stack, and RMS management, ready to design into a product built in volume. For OEMs and integrators in access control, EV charging, metering, and unattended machinery, that is exactly the gap it fills.
For a deeper technical comparison with Teltonika’s other Cat 4 hardware, including the global RUT281, RUT981, and RUT986, see the detailed write-up on IoT Portal.
Written by Peter Green. Peter has spent 25 years in UK telecoms and IoT, working with cellular routers, antennas, and SIM connectivity across industrial and utility deployments.