#2024, #usecase, #modems

February 21, 2024

In the age of connectivity, network devices stand strong facilitating seamless communication. From personal Internet access to industrial IoT applications, they play a crucial role in enabling data transmission over diverse networks. 


The world of connectivity devices

Many connected devices have one thing in common: the function of facilitating communication between different appliances or networks, which enables the exchange of data, information, or signals.

That being said, it’s important to determine the differences between connected devices that might seem alike but are nevertheless different. For instance, although gateways, routers and modems share many same characteristics, they have some significant differences as well.


Usually, gateways are designed to have one interface, meaning that they can connect only one end device to the Internet. For instance, our TRB143 cellular gateway, which comes with the M-Bus interface, is a great fit for district heating systems. Only a single device per heating system allows end clients to remotely and automatically collect data, opening the door for enhanced energy efficiency while keeping integration easy and saving costs.

Another great example is our TRB142 industrial gateway. Equipped with the RS232 serial interface, it’s the perfect choice for smart grid communication and offers efficient monitoring and management of energy grid operations.

Routers, on the other hand, provide Internet connectivity to multiple end devices through multiple interfaces. If you’re upgrading out-of-band management a cellular router like our RUT956 is exactly what you need. It tackles the challenge of slow connection speeds with LTE Cat 4 connectivity enhanced by a myriad of network reliability features and remote management.

All about cellular modems


Unlike routers and gateways, modems have only one function – to facilitate an Internet connection.

The term "modem" is an abbreviation for "modulator-demodulator." These devices perform modulation by converting digital signals from a computer into analogue signals suitable for transmission over analogue communication lines. They also perform demodulation via a reversing process: converting incoming analogue signals back into digital signals that can be understood by the receiving device.

Furthermore, calling a router or gateway a “modem” would be incorrect. Commonly-used term of "modem router combo", referring to the fact that each router and gateway includes a modem inside of them, is an old bad habit that refuses to die out. Really, every router is a "modem router combo".

At the same time, some routers are designed to have more than one LTE modem inside of them. For instance, our RUTX12 contains two modems for dual, simultaneous LTE Cat 6 connections with instant failover switching.

Modems don’t have data protection software or a firewall. Additionally, they are controlled by AT commands, a set of instructions that consists of short text strings which can be combined to produce commands for operations. These operations consist of dialling, managing SMS functions, and changing the parameters of the connection.

Moreover, they have only one task: to send data from point A to point B without changing it. They cannot create a connection without the help of the device they are connected to, meaning that they are devices for connectivity without network control capabilities. Their largest advantages are longevity and low power consumption.

When should you use a modem?

Knowing when to deploy a modem over a router or gateway is a great way to save costs. Teltonika Networks presently has two modems in its product portfolio: TRM240 and TRM250.

Other benefits of our TRM240 and TRM250 4G LTE modems are their compact sizing, easy installation, and a USB interface. In addition to this, our cellular modems provide LTE Cat 1 connectivity, resulting in affordable pricing while maintaining high quality.


It’s safe to say that cellular modems have fewer features than other networking devices, namely gateways and routers. However, they also boast cost efficiency with lower pricing, so knowing when you could deploy a modem instead of network devices is really beneficial.

Network control is not necessary in some simple industrial settings. For instance – operating a coffee machine. In this case, the coffee machine is connected to a modem, like our TRM250 cellular modem, via a wired data connection. The modem is wirelessly connected via 4G LTE, allowing a service centre to access the data. These types of settings don’t require network control, allowing you to solve the networking challenge by using a cellular modem.

Another great example is using our TRM250, to connect payment terminals to the Internet. In this case, the payment terminal is connected to the cellular modem via a wired data connection while the modem is connected to the Internet via wireless data, providing connectivity to the payment terminal.

Moreover, modems are also used by people counter systems that count the number of people passing through a certain area, such as people entering or exiting a shopping mall. To make these systems usable, continuous connectivity is a must. That’s where our TRM240 trusted cellular modem comes in handy, connected to the people counter via a wired connection and to the Internet wirelessly.

Although both TRM-series networking devices are very similar to one another, they do have a key difference. The TRM240 cellular modem is great for upgrading legacy IoT equipment with cost-efficient connectivity, and the TRM250 cellular modem works wonders in providing cost-efficient Internet connectivity in remote monitoring applications. This is because of a difference in their backward compatibility: the TRM240 supports 3G, while the TRM250 supports 2G and NB-IoT.

Finally, if you need the best modem for your industrial solution – you cannot go wrong with our TRM-series devices. They will make your IoT dreams come true!

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