Basics Of Remote Cellular Access – Choosing A Modem

These days, we’re blessed with cellular data networks that span great swathes of the Earth. By and large, they’re used to watch TV shows and argue with strangers online. However, they’re also a great tool to use to interact with hardware in remote locations, particularly mobile ones where a wired connection is impractical.

In this series, we’re taking a look at tips and tricks for doing remote cellular admin the right way. First things first, you’ll need a data connection – so let’s look at choosing a modem.

Options Abound

When shopping around for cellular data modems, it can be difficult to wade through the variety of options out there and find something fit for purpose. Modems in this space are often marketed for very specific use cases; at the consumer level, many are designed to be a no-fuss home broadband solution, while in the commercial space, they’re aimed primarily to provide free WiFi for restaurants and cafes. For use in remote admin, the presence of certain features can be critical, so it pays to do your research before spending your hard earned money. We’ve laid out some of the common options below.

Consumer Models

The Sierra Aircard 320U is ancient now, with limited frequency bands available. Its flimsy flexible connector is also a drawback. However, its ease of configuration with Linux systems makes it a dream to use in remote access situations. Unlike many others, it acts as a Direct IP connection, not appearing as a separate router.

Many telecommunications providers around the world sell cheap USB dongles for connecting to the Internet, with these first becoming popular with the rise of 3G. They’re somewhat less common now in the 5G era, with the market shifting more towards WiFi-enabled devices that share internet among several users. These devices can often be had for under $50, and used on prepaid and contract data plans.

These devices are often the first stop for the budding enthusiast building a project that needs remote admin over the cellular network. However, they come with certain caveats that can make them less attractive for this use. Aimed at home users, they are often heavily locked down with firmware that provides minimal configuration options. They’re generally unable to be set up for port forwarding, even if you can convince your telco to give you a real IP instead of carrier-grade NAT. Worse, many appear to the host computer as a router themselves, adding another layer of NAT that can further complicate things. Perhaps most frustratingly, with these telco-delivered modems, the model number printed on the box is often not a great guide as to what you’re getting.

A perfect example is the Huawei E8327. This comes in a huge number of sub-models, with various versions of the modem operating in different routing modes, on different bands, and some even omitting major features like external antenna connectors.  Often, it’s impossible to know exactly what features the device has until you open the box and strip the cover off, at which point you’re unable to return the device for your money back.

All is not lost, however. The use of VPNs can help get around NAT issues, and for the more adventurous, some models even have custom firmware available on the deeper, darker forums on the web. For the truly cash strapped, they’re a viable option for those willing to deal with the inevitable headaches. There are generally some modems that stand out over others in this space for configurability and ease of use. This writer has had great success with a now-aging Sierra Aircard 320U, while others have found luck with the Huawei E3372-607. As per earlier warnings though, you don’t want to accidentally end up with an E3372-608 – thar be dragons.

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