Back to blog
IoT & M2M Iridium

September 19, 2023

RUDICS vs Certus 100: is it time to make the switch?

Iridium RUDICS (Router-Based Unrestricted Digital Internetworking Connectivity) was devised in the early 2000s as a means of allowing remote devices to connect to internet-connected servers using TCP/IP. The previous system, dial-up data, had a hefty overhead every time the service was activated, as a series of checks needed to take place before data could be transmitted.

RUDICS improved upon this by connecting the call to a predefined IP address, dispensing with the checks, and making connection almost instantaneously. This had the advantage of requiring less power at the remote transmitter end, lowering latency, and generally being a more efficient means of accessing the Iridium system.

RUDICS was – and still is – used for solutions that have multiple remote units in the field reporting back to an end point. Data buoys, water level stations, Unmanned Autonomous Vessels (UAVs), geotechnical and structural monitoring solutions, weather stations and many more applications have relied upon RUDICS for two-way communication for close to two decades.

Iridium RUDICS applications banner

In 2019, Iridium launched its (at the time of writing) newest satellite capability, Iridium Certus. Leveraging the advanced technology on the latest generation of Iridium satellites, Iridium Certus is available in three speed classes: Certus 100, which is intended for IoT applications; Certus 200, which is good for basic internet and voice, and Certus 700, which delivers the fastest L-band internet broadband speeds currently available, up to 704 kbps.

When we’re comparing RUDICS to Certus, we’re exclusively talking about Iridium Certus 100. They’re both aimed at the same use case of connecting remote devices to servers using TCP/IP (although Certus 100 has an alternative option here – more on that later).

What are the key differences between RUDICS and Certus 100?

Certus 100 has faster data speeds

RUDICS transmits data at 2.4 Kbps; Certus 100 transmits data at 22 Kbps, and the downlink is 88 Kbps – almost 40 times faster. This means that you can transmit more data, more frequently.

Costs / billing mechanism

RUDICS is charged per minute, rather than the Certus 100 charging model of per byte of data transmitted. This makes RUDICS more expensive than Certus 100 for many applications; it’s possible, even probable, that you’re paying for connectivity time you don’t need.

RUDICS is circuit-switched

RUDICS is circuit-switched, which means the ‘call’ between the remote device and the server has to be maintained. It’s not fault tolerant if your view of the satellite is temporarily obscured, or the server goes offline.

Certus 100 is packet-switched

Certus 100 is a packet-switched network, sending data in small and optimised packets which are much less likely to be ‘dropped’ mid-transmission.

In our view, there are very few instances where Certus 100 will not present a more reliable, cost-effective and scalable solution for remote data transfer than RUDICS.

It doesn’t stop there: while Certus 100 supports TCP/IP-based connectivity, it also offers users the ability to send data via Iridium Messaging Transport (IMT). This is a message-based transmission protocol which allows you to send and receive messages of up to 100,000 bytes.

This could facilitate additional sensor readings, greater data resolution, photographs or even low-resolution video. Just as importantly, sending data via IMT will substantially lower the cost of data transmission because there’s no TCP/IP overhead in a message-based service; you’re only billed for your (successfully delivered) data payload.

Get in touch

If you’re currently using RUDICS, let’s talk: based on your current data usage we’ll be able to advise if you can save money by switching to Certus 100, and we can work through any technical implications of doing so.

We’ve been Iridium partners since 2005, so we’re well placed to provide you with an experienced, objective perspective on the right connectivity solution for you.