Industrial Routers and Gateways Explained: Connecting Remote Equipment, PLCs and Industrial Networks

Quick overview: This guide explains industrial routers and gateways and the practical checks that help you understand and plan an installation. Use the contents below to go directly to the relevant section.

Industrial routers and gateways are widely used to connect remote equipment, automation systems and operational networks. They can provide cellular or wired WAN connectivity, route traffic between networks, create secure remote-access paths and, on suitable models, bridge or translate communications between different interfaces or protocols.

The terms router and gateway are sometimes used loosely, which can make purchasing confusing. A device described as an industrial gateway may perform routing, serial conversion, protocol conversion, data acquisition or several of these functions. The actual interfaces and supported functions therefore matter more than the product label alone.

This guide explains the practical differences and the information technical and purchasing teams should confirm before selecting industrial routers or gateways.

What Is an Industrial Router?

An industrial router connects different IP networks and forwards traffic between them according to its configuration.

Depending on the model, an industrial router can provide interfaces such as:

• Ethernet LAN ports
• Ethernet WAN
• 4G or 5G cellular connectivity
• Wi-Fi
• Serial interfaces
• Digital inputs or outputs
• GNSS or GPS functions

Industrial routers are commonly designed for DIN-rail or panel installation and can support DC power, extended operating temperatures and other features suited to control panels, remote sites and infrastructure environments.

What Is an Industrial Gateway?

The word gateway can describe several different functions.

A gateway may connect networks, convert between serial and Ethernet interfaces, translate between industrial protocols, collect field data or provide an edge connection to another system.

Because the term is broad, never assume that a product described as a gateway performs the specific conversion required by an application.

The supported interfaces, protocols and operating modes must be checked in the manufacturer's documentation.

Router vs Gateway vs Ethernet Switch

These devices perform different roles.

An Ethernet switch primarily connects devices within an Ethernet network.

A router connects different IP networks and routes traffic between them.

A gateway is a broader term and can provide interface conversion, protocol conversion, data handling or network connectivity depending on the device.

A project may use all three. For example, an industrial switch can connect local PLCs and HMIs, while an industrial cellular router provides the WAN connection and a protocol gateway interfaces with legacy serial equipment.

Why Use an Industrial Cellular Router?

Cellular routers are useful where a remote site requires IP connectivity but fixed communications infrastructure is unavailable, impractical or used only as one part of a resilient architecture.

Applications can include:

• Pump stations
• Reservoirs
• Boreholes
• Remote telemetry sites
• Water and wastewater infrastructure
• Industrial machines
• Mining infrastructure
• Remote electrical installations
• Environmental monitoring
• Distributed automation systems

4G vs 5G

Both 4G and 5G industrial routers are available.

The correct choice depends on network coverage, required performance, device lifecycle, network architecture and project requirements.

A 5G-capable router does not automatically provide better connectivity at every site. If suitable 5G coverage is unavailable, the practical connection may still depend on 4G or another supported cellular technology.

Before specifying a router, consider the mobile network technologies actually available at the installation location.

SIM Cards and Mobile Network Service

A cellular router normally requires a suitable SIM or other supported mobile-network service.

The router itself does not automatically include mobile data service unless this is explicitly part of a supplied solution.

Purchasing should therefore distinguish between the hardware and the cellular service required to operate it.

What Is an APN?

APN stands for Access Point Name.

The APN is part of the configuration used by cellular equipment to connect to the mobile operator's packet data network.

The correct APN settings depend on the SIM and mobile network service. Some applications use standard public internet APNs, while private or enterprise services can use different configurations.

If a project requires a private APN, fixed addressing or other managed mobile-network service, this should be confirmed separately from the router hardware.

Public vs Private IP Addresses

Remote access requirements are affected by the type of IP connectivity provided by the mobile operator.

Many mobile services place devices behind carrier-grade NAT or other network address translation, meaning the router may not have a directly reachable public IPv4 address.

This can affect designs that expect unsolicited inbound connections from the internet.

VPN architectures, private APNs, cloud-managed connectivity or other suitable approaches can be used depending on the application and cybersecurity requirements.

What Is NAT?

Network Address Translation, or NAT, allows addresses to be translated as traffic passes between networks.

NAT is commonly used when private local IP addresses need to communicate through another network or internet connection.

Industrial routers can provide different NAT functions depending on the model and configuration.

NAT should be designed deliberately because address translation can affect troubleshooting and some industrial communications.

Port Forwarding

Port forwarding directs selected inbound network traffic to a particular internal device or service.

Although technically useful in some architectures, exposing industrial devices directly to public networks can create serious cybersecurity risks.

Remote access should use an appropriate security architecture rather than enabling unrestricted port forwarding simply because it is easy to configure.

VPNs for Remote Industrial Connectivity

A Virtual Private Network, or VPN, creates an encrypted communication path between authorised endpoints or networks.

Industrial routers can support technologies such as IPsec, OpenVPN, WireGuard or other VPN mechanisms depending on the manufacturer and model.

VPN capability should be checked against the site's cybersecurity policy, authentication requirements and central infrastructure.

A router supporting the word VPN does not guarantee compatibility with every VPN platform or configuration.

Remote PLC Access

Industrial routers are often used to provide authorised remote access to PLCs, HMIs and other automation equipment.

This can assist with diagnostics, monitoring or approved maintenance activities.

However, remote PLC access should not be treated as simply connecting the PLC to the internet.

Appropriate segmentation, authentication, VPN architecture, firewall rules, access control, logging and organisational procedures should be used according to the risk and site requirements.

LAN and WAN Ports

Industrial routers commonly distinguish between LAN and WAN interfaces.

LAN ports connect local devices or local network infrastructure.

WAN interfaces connect the router to an upstream network or internet service.

Some devices allow Ethernet ports to be configured for different roles. Others have fixed interfaces.

When selecting a router, specify how many local Ethernet devices must connect and whether a wired WAN connection is required in addition to cellular connectivity.

Dual SIM Routers

Some industrial cellular routers support two SIM cards.

Dual SIM capability can allow the router to use an alternate SIM according to configured conditions, which can improve communications resilience where suitable network services are available.

However, two SIM slots do not automatically guarantee uninterrupted connectivity. Both SIMs may depend on the same operator, tower, infrastructure or coverage conditions.

Failover behaviour and operator diversity should be considered as part of the complete communications design.

Dual WAN and Failover

Some industrial routers can use multiple WAN paths such as wired Ethernet and cellular connectivity.

This can allow a primary connection to use fixed infrastructure while cellular provides backup connectivity.

Failover detection, recovery behaviour and routing policies vary between devices and should be verified where connection resilience is important.

Load Balancing

Selected routers can distribute traffic across more than one WAN connection.

This is different from simple failover, where one connection is normally active and another is used when the primary path fails.

If load balancing is required, confirm that the router supports the intended mode and that the application is compatible with the resulting network behaviour.

Serial Interfaces

Industrial gateways and some routers provide serial interfaces such as RS-232 or RS-485.

This can allow older or serial-only industrial equipment to communicate with Ethernet-based or remote systems.

The presence of a serial port does not automatically mean the device converts the application protocol.

Serial electrical conversion and industrial protocol conversion are separate functions.

Serial Device Servers

A serial device server transports serial communications over an IP network.

Depending on the product, it can provide virtual COM-port functionality, TCP server/client modes or other serial-over-Ethernet functions.

This can be useful when a serial device needs to communicate across an Ethernet network without changing the underlying application protocol.

Protocol Gateways

A protocol gateway can translate data between supported industrial protocols.

Examples can include conversion between Modbus RTU and Modbus TCP or between other specifically supported protocols.

Protocol translation is not universal. The gateway must explicitly support the protocols, roles, data mapping and functions required by the application.

Modbus RTU to Modbus TCP Gateways

One common gateway application connects Modbus RTU devices on an RS-485 network to Modbus TCP systems on Ethernet.

Important requirements can include:

• Serial baud rate
• Parity
• Stop bits
• Modbus device addresses
• Number of serial devices
• Gateway operating mode
• Ethernet addressing
• Number of simultaneous TCP connections
• Required register polling behaviour

A gateway can provide the communication bridge, but the PLC, SCADA or other application still needs the correct register addresses, data types and scaling for the connected devices.

A Gateway Does Not Automatically Understand Every PLC

Two products having Ethernet ports does not mean they communicate using the same application protocol.

Likewise, a gateway marketed for industrial use does not automatically translate between every PLC family, fieldbus and Ethernet protocol.

When protocol conversion is required, specify both sides clearly. For example:

Modbus RTU master ↔ Modbus TCP server

is more useful than requesting an 'industrial gateway'.

Telemetry and Remote Monitoring

Industrial routers and gateways are frequently used in telemetry systems where remote equipment sends information to a central monitoring platform.

Depending on the architecture, data can come from PLCs, RTUs, meters, instruments or other field devices.

The communications hardware is only one part of the system. The central server, SCADA platform, protocol, addressing, cybersecurity and data architecture must also be compatible.

Industrial Router Antennas

Cellular routers require suitable antennas unless an appropriate antenna is integrated into the device.

External antennas are common in industrial installations, particularly where the router is mounted inside a metal enclosure.

When selecting an antenna, consider:

• Supported cellular frequency bands
• 4G or 5G requirements
• MIMO requirements
• Connector type
• Cable length
• Indoor or outdoor installation
• Mounting method
• Environmental rating

What Is MIMO?

Multiple Input Multiple Output, or MIMO, uses multiple antenna paths to improve wireless communication performance and reliability in compatible systems.

Modern cellular routers can require two or more antenna connections for particular cellular technologies and performance modes.

Do not assume that one antenna is sufficient simply because the router powers up and registers on the network.

Antenna Placement Matters

A high-quality router cannot compensate for every poor antenna installation.

Signal performance can be affected by:

• Metal enclosures
• Buildings and structures
• Terrain
• Distance from the serving site
• Interference
• Antenna orientation
• Feeder cable losses
• Frequency band

Where signal conditions are difficult, antenna selection and placement should be treated as part of the communications design.

Signal Strength and Signal Quality

Cellular diagnostics can include measurements such as RSSI, RSRP, RSRQ and SINR depending on the network technology and router.

Signal strength alone does not provide the complete picture. Signal quality and network loading can also affect connection performance.

For remote sites, routers that expose useful cellular diagnostics can simplify commissioning and troubleshooting.

External Antenna Cable Length

Coaxial antenna cable introduces signal loss.

Very long antenna leads can reduce the benefit of placing an antenna in a better location, particularly at higher frequencies.

Where possible, antenna placement, cable type and cable length should be considered together rather than extending an unsuitable cable indefinitely.

Industrial Wi-Fi

Some industrial routers include Wi-Fi functionality.

Wi-Fi can be used as a local access method, client connection or WAN path depending on the router.

Requirements such as frequency band, antenna configuration, security mode and access policy should be specified if Wi-Fi forms part of the application.

Power Supply Requirements

Industrial routers commonly operate from DC supplies used in control panels.

Before ordering, confirm:

• Permitted input voltage range
• Maximum power consumption
• Connector or terminal type
• Whether a power supply is included
• Whether redundant power inputs are supported
• Any power requirements for USB or connected accessories

For remote infrastructure, the communications equipment should also be included in backup-power and energy calculations where continuity is required.

DIN Rail Mounting

DIN-rail mounting is common for industrial routers and gateways installed in electrical or automation panels.

Check the required clearances, antenna cable routing, ventilation and connector access before finalising the panel layout.

Operating Temperature

Remote cabinets and plant environments can experience temperatures well outside normal office conditions.

Confirm the router or gateway's rated operating range against the expected internal enclosure temperature, not only the average outdoor ambient temperature.

SIM cards, power supplies and other accessories also need to be suitable for the environment.

Digital Inputs and Outputs

Some industrial routers include digital I/O.

These can be used for functions such as local alarm indication, monitoring a contact or controlling a supported output depending on the device.

I/O voltage, electrical characteristics and supported software functions must be checked before integrating these points into a control system.

GNSS and GPS

Selected industrial routers provide GNSS positioning functions.

This can be useful for mobile assets, location reporting or time-related applications.

GNSS normally requires an appropriate antenna and suitable satellite visibility.

Cloud Management

Some manufacturers provide cloud platforms for managing industrial routers remotely.

Capabilities can include configuration, status monitoring, firmware management, VPN orchestration and device inventory.

Cloud management can simplify fleets of remote routers, but organisations should assess subscription requirements, data handling, cybersecurity policy, platform availability and lifecycle implications.

Cybersecurity Is Not Optional

An industrial router can create a path between operational equipment and external networks. That makes cybersecurity a core design requirement.

Depending on the system, controls can include:

• Firewalls
• VPNs
• Network segmentation
• Strong authentication
• Least-privilege access
• Disabling unused services
• Firmware management
• Configuration backups
• Logging and monitoring
• Controlled maintenance access
• Physical security

Default credentials should be changed and unnecessary remote-management services should not be exposed to public networks.

Industrial Router vs Ordinary Consumer Router

A consumer router can provide internet connectivity, but industrial applications can require characteristics such as:

• DIN-rail mounting
• DC power input
• Extended temperature range
• Dual SIM
• Industrial cellular diagnostics
• Serial interfaces
• Industrial VPN functions
• Remote management
• Watchdog and recovery functions
• More robust mechanical construction

This does not mean a device is appropriate simply because it is labelled industrial. The actual specification must match the project.

Watchdog and Connection Recovery

Remote sites need to recover from communication interruptions without frequent site visits.

Some industrial routers provide watchdog functions that can monitor connectivity and restart an interface, modem or device according to configured conditions.

The exact behaviour differs between manufacturers and should be verified if automated recovery is important.

Configuration Backup

Industrial routers can contain substantial configuration including VPN credentials, firewall rules, APN settings, routes and remote-management settings.

Configuration backups should be maintained according to site procedures so a failed router can be replaced and restored efficiently.

Sensitive configuration files should be protected appropriately.

Firmware and Lifecycle

Routers and gateways are software-driven devices. Firmware affects functionality, cybersecurity and compatibility.

For long-life industrial projects, consider:

• Manufacturer support
• Firmware availability
• Security updates
• Product lifecycle
• Replacement models
• Configuration migration

Lowest initial purchase price may not be the only relevant factor for equipment expected to remain in remote infrastructure for many years.

Common Industrial Router Selection Mistakes

Common mistakes include:

• Ordering by 4G or 5G label without checking supported bands
• Not specifying the number of Ethernet ports
• Forgetting antenna requirements
• Not checking antenna connectors
• Ignoring MIMO requirements
• Assuming a SIM or data service is included
• Not considering public versus private addressing
• Assuming dual SIM automatically provides network redundancy
• Ignoring VPN compatibility
• Using port forwarding where a more secure remote-access design is required
• Not checking input voltage
• Ignoring operating temperature
• Assuming every gateway performs protocol conversion
• Not specifying serial interface requirements

Replacing an Existing Industrial Router

When replacing a router, provide the exact manufacturer and model number wherever possible.

Also record:

• SIM count and mobile operators
• Cellular technology
• Antenna configuration
• Ethernet connections
• WAN connection
• Serial interfaces
• VPN configuration
• APN requirements
• Power input
• Mounting
• Operating environment
• Any cloud-management platform

A hardware replacement may require configuration migration and network coordination. Matching the physical interfaces alone is not enough.

A Practical Planning Checklist

When requesting a quotation, provide as much of the following as possible:

• Application: ___
• Router, gateway or unsure: ___
• Cellular requirement: 4G, 5G or other
• Mobile network/operator: ___
• SIM slots required: ___
• Ethernet LAN ports: ___
• Ethernet WAN required: yes or no
• Wi-Fi required: yes or no
• Serial interfaces: RS-232, RS-485 or other
• Protocols requiring conversion: ___
• VPN requirement: ___
• Remote access requirement: ___
• Private APN or fixed IP requirement: ___
• Dual SIM or WAN failover: ___
• Antenna requirement: ___
• Input voltage: ___
• Mounting: DIN rail or other
• Operating temperature: ___
• Installation environment: ___
• Existing model if replacing: ___
• Quantity: ___

If protocol conversion is required, identify the protocol and role on both sides of the gateway rather than requesting a generic protocol converter.

For router and gateway enquiries, provide the required interfaces, cellular technology, protocols, remote-access requirements and installation environment wherever possible. For replacement equipment, the existing manufacturer and model number is particularly useful.

Technical Note

This article provides general industrial networking information. Remote access, routing, VPNs, firewall rules, cellular services, protocol conversion, cybersecurity, antenna design and network architecture must be assessed for the specific installation. Manufacturer documentation, applicable standards, organisational cybersecurity requirements and site procedures take precedence. Critical network design and configuration should be undertaken or verified by appropriately competent personnel.

Related catalogue examples: Industrial Networking. For an equipment enquiry, contact Softcore Group Industrial Solutions at info@softcoregroup.co.za.