100 KB
data per message ↑
Iridium Messaging Transport (IMT) Devices
IMT is the natural successor to Short Burst Data (SBD), and allows faster throughput and significantly larger messages (up to 100 KB). Depending on your usage, IMT is also likely to represent a cost-saving over SBD.
Ground Control has worked closely with Iridium since the very beginning of Certus 100 / IMT, and we are experts in this technology.
Options for Accessing IMT
There are two Iridium modules that utilize the IMT service: the 9770 and the 9704. However, they’re quite distinct in terms of functionality, and their airtime is priced differently. The 9770 module can send data over both IMT and Iridium Certus 100, so has the capability to use both message and IP-based transmissions. The 9704 module only sends via IMT; there is no IP option.
The trade-off is that the 9704 is smaller, lighter, and uses far less power than the 9770. It weighs about the same as its SBD-based predecessor, the 9603N module (12 g vs 11.4 g), but is 34% smaller than the 9603N.
How Does IMT Pricing Compare to SBD Pricing?
In our assessment, SBD is lower cost if you’re sending less than 7-10 KB of data per month. IMT via the 9704 module is best if you’re sending up to 55-60 KB of data per month, and IMT via the 9770 module is most economical if you’re sending over 60 KB of data per month.
This is a little over-simplified, and doesn’t take into account commitment, pools, hardware cost, power consumption, physical size, antennas etc., but serves as a guide.
Devices Utilizing the 9704 Module
RockBLOCK Pro and Pro OEM have been designed to make integrating your solution with IMT easy. These devices manage message queuing, retries, and network issues, reducing development complexity. They have built-in GNSS and configurable I/O options, and support legacy 9603 AT commands, making migration for existing SBD customers simple and hassle-free.
RockBLOCK 9704 is a compact, lightweight successor to RockBLOCK 9603. Like its predecessor, it adds an antenna (patch or external), power supply requirements, and a simple serial interface to the bare module, making integration easy for space-constrained enclosures.
Devices Utilizing the 9770 Module
These are our RockREMOTE devices, and they’re highly versatile. The RockREMOTE Rugged is the most flexible device here, with the ability to transmit using IMT, Certus 100 (IP), and cellular where available. It also features hosted applications so can be used as a gateway / for edge computing.
The RockREMOTE Mini and Mini OEM are satellite-only, but can flip between IP and message-based services depending on the application. Both are optimized for low power draw, making them suitable for solar / battery powered use cases.
Why Isn’t the ‘Bare’ 9704 Module Listed Here?
Working with the bare 9704 module is reserved for companies collaborating closely with Iridium, or an Iridium partner, and there are comprehensive certification requirements. For this reason it’s not offered up for sale online, but if you are interested in developing with the bare module, please get in touch.
100 KB
data per message ↓
~10 s
latency (variable)
Iridium Messaging Transport (IMT) Airtime
Right now, you’ll pay a different rate for utilizing IMT via the 9704 module vs. the 9770 module. Excluding all other variables (hardware price, contract length etc.), if you’ll be using between 10-55 KB of data per month, then IMT via the 9704 module is more cost effective. Over 55 KB per month, and IMT via the 9770 module is lower cost
| Example Plan: | 0 KB | 25 KB | 50 KB |
|---|---|---|---|
| Price Per Month (USD): | $17.00 | $21.00 | $25.00 |
| Inclusive Data: | 0 KB | 25 KB | 50 KB |
| Minimum Message Size | 75 Bytes | 25 Bytes | 25 Bytes |
| Activation Fee: | $17.00 | $21.00 | $25.00 |
| Overage per KB | $0.50 | $0.50 | $0.50 |
| Commitment | 3 Months | 3 Months | 3 Months |
Free Access to Cloudloop Subscription Manager and Cloudloop Data with Any Plan.
| Example Plan | 1 MB | 5 MB | 10 MB | 50 MB |
|---|---|---|---|---|
| Price Per Month: | $35.00 | $53.00 | $85.00 | $200.00 |
| Inclusive Data | 1 MB | 5 MB | 10 MB | 50 MB |
| Activation Fee | $15.00 | $15.00 | $15.00 | $15.00 |
| Overage per MB | $15.00 | $12.00 | $10.00 | $7.00 |
| Commitment | 3 Months | 3 Months | 3 Months | 3 Months |
Free Access to Cloudloop Subscription Manager and Cloudloop Data with Any Plan.
Comparing Satellite IoT Connectivity
It’s tricky to compare airtime services because so much depends on how much data you need to send, but as a rough guide, we’ve put together the following comparison points. Get in touch if you’d like any help deciding what will work best for you.
| Service | Iridium SBD | Iridium Certus 100 | Viasat IoT Pro |
|---|---|---|---|
| Connection Type | Message-based | IP-based | IP-based |
| Typical Connection Speed: | 270 / 320B per Message | 22 / 88 Kbps | 448 / 464 Kbps |
| Satellite Orbit: | Low Earth Orbit (LEO) | Low Earth Orbit (LEO) | Geostationary |
| Total Cost of Ownership: | Very Low | Medium | Low |
| Power Usage: | Very Low | Medium | Low |
| Connection Frequency: | On Demand | Frequently Connected | Frequently Connected |
| Great For: | Very small amounts of data from individual sensors | Fixed or mobile IoT applications which require IP connection | Fixed IoT applications with larger amounts of data to transfer via an IP connection |
Is Iridium Messaging Transport right for your project?
Ground Control has worked closely with Iridium since the very beginning of Certus 100 / IMT, and we are experts in this technology.
Complete the form or email hello@groundcontrol.com, and one of our expert team will be happy to provide a custom recommendation for the best airtime for your particular application.
We will respond to your inquiry within one working day.