RockBLOCK 9603

SKU: FP-RB-9603

The smallest and lightest version in our RockBLOCK family, the RockBLOCK 9603 Compact Plug-and-Play Satellite Transmitter is targeted primarily at systems integrators and product developers where space inside your enclosure is at a premium.

It’s being used to transmit sensor data from data buoys, fire prevention systems, water level gauges, weather stations, animal tracking collars, USVs and UAVs, LoRaWAN gateways, and many, many more.

RockBLOCK 9603

$ 302.00

SKU: FP-RB-9603 Category:
Coverage Data sheet

Small but mighty for satellite IoT connectivity

RockBLOCK 9603 is the smaller version of our standard RockBLOCK product. It has the same capabilities, but is specifically designed to be as small and light as possible and can send and receive short messages from anywhere on Earth with a view of the sky.

It is compatible with Arduino, Windows, Mac and Linux computers (including Raspberry Pi), and many other platforms with serial or USB ports.


The RockBLOCK 9603 has a small form factor Molex connector to link the serial, power, and signalling lines to your controller. This may be marginally harder to use for hobbyists than the 0.1″ dot pitch header used on the standard RockBLOCK product. At the heart of RockBLOCK 9603 is an Iridium 9603 modem.

The RockBLOCK hosts the 9603 and provides it with an antenna and its power supply requirements. It exposes the modem’s serial interface via a breakout connector over serial and also offers an SMA connector for external antenna usage.

Key Features
Technical Specification
Register your RockBLOCK
  • Plug and play satellite communication
  • Full 2-way communication system
  • Optional SMA connector, for external antenna
  • Truly Global operation, pole to pole
  • Transmit: 340 bytes per message
  • Receive: 270 bytes per message
  • Available as a PCB for integration
  • Integrated antenna and power conditioning
  • Powered via USB or direct-header connection
  • Data via e-mail or directly to your web-service
  • Get started without support using detailed developer docs
  • Powered By Direct Header Connector, 5v; 100mA minimum
  • Power Consumption: max 450mA (100mA required)
  • Weight: 1.3 oz (36 grams) including antenna
  • Size: 1.8″ x 1.8″ x 0.6″ (45.0 x 45.0 x 15.0mm)
  • Mounting Holes: Two on PCB
  • Header Connector: Molex 51021
  • Testing: CE | FCC | Iridium Approved
  • Built in Antenna: Yes (or use optional SMA connector for external antenna)
  • Storage and Operating Temperature: -40 to 185F (-40 to 85C)
  • Operating Environment: < 75% Relative Humidity
  • Ideal For integration into existing devices
  • Waterproofing: RockBLOCK 9603 is not waterproof. If you need a waterproof unit, look at the RockBLOCK Plus

Ground Control offers Iridium SBD airtime both as a prepaid service plan, and as an annual contract for companies planning a larger deployment of devices. Full pricing plans can be found on our Short Burst Data Pricing page.

If you choose our prepaid, or pay as you go option, line rental is paid in blocks of 1 month, and allows the RockBLOCK Plus to exchange information with the Iridium satellite network. You only pay for months in which you wish to use the RockBLOCK Plus. No annual contract is required. Line rental costs $17.00 per month.

Credits are used each time you transmit. 1 credit is used per 50 bytes (or part thereof) of message sent or received. 1 credit is also used if you check your mailbox and there are no messages waiting (A mailbox check). Credits do not expire, even if you are paying no line rental. Credits are shared/pooled between all of the devices on your account

Please note, while our pay-as-you-go service plans offer great flexibility for development purposes, we know they are not suitable for everyone. If you are planning a large deployment of devices (100+) and are willing to commit to airtime contracts of 12 months or more, please get in touch. We have access to various plans which may suit you better.

per Credit:
Bundle Price:
Line Rental (per month):
50 Credits
100 Credits
200 Credits
500 Credits
1,000 Credits
2,000 Credits
5,000 Credits

The RockBLOCK management system allows users to amend their account details, manage RockBLOCKs, top-up accounts, review invoice details, and set-up communication between HQ, individual devices and device groups.

Upon receiving your RockBLOCK(s), first time users will need to log on to our registration page:

Having trouble registering?

If you are not registering new units, there’s a very high chance they have been already registered somewhere else. Contact, including your RockBLOCK serial numbers and IMEIs so that we can look into the issue.

Iridium SBD Coverage

In Low Earth Orbit (LEO) the Iridium satellite constellation is able to deliver many benefits for IoT applications, not least reduced ping time. As these satellites are much closer to the Earth’s surface, the latency – ping time, is typically less than one second.

Utilizing omni-directional antennas, data will be accepted by the closest satellite and then ‘handed off’ as appropriate to the next. Using a mesh of 66 satellites in total, the SBD service is ideal for mobile applications anywhere on the planet including both poles.

Iridium’s truly global, low-latency SBD service is perfect for monitoring and updating status on everything from weather balloons to fleet telematics. Used for tracking and IoT applications alike, this service works anywhere on Earth without expensive roaming charges or the need for multiple service agreements.

Iridium Coverage Map – Real Time Tracking

Considering the RockBLOCK 9603?

Great, click the button below to start a dialogue with one of the team and see how the RockBLOCK 9603 fits with your application.



How does it work?

RockBLOCK uses the Iridium satellite network. Specifically, it uses an Iridium service called ‘short burst data’ (SBD). At the heart of RockBLOCK 9603 is an Iridium 9603N modem. The RockBLOCK hosts the 9603N and provides it with an antenna and its power supply requirements. It exposes the modem’s serial interface via USB (or directly – PCB assembly version only). Full documentation for the 9603 modem can be found here: Iridium 9603 SBD Transceiver Product Developers Guide.

How is it powered?

RockBLOCK takes its power from the direct header connector or alternatively via the optional FTDI/USB adaptor. If you’re using the PCB assembly version with a direct header, your host needs to supply a minimum of 100mA @ 5V.

How much data can I send/receive?

340 bytes FROM RockBLOCK.
270 bytes TO RockBLOCK.

How quickly can I send a message?

Testing shows that it generally takes around 20 seconds from power-up to successful transmission, with a perfect view of the sky. With a very restricted view, it may take several minutes.

How frequently can I send a message?

You should be able to complete an Iridium SBD session roughly every 10 seconds, assuming a perfect view of the sky.

Can I connect an external antenna?

Yes. There’s a version of the RockBLOCK available with an SMA connector (instead of the built-on antenna) which allows you to attach an external Iridium antenna.

Unit refuses to give me data using the SBDRT command

If you’re using the SBDRT command and the modem appears to ‘hang’ when you issue the command, it’s probably due to flow control configuration. The default state for the RockBLOCK and RockBLOCK Plus units has flow control turned ‘on’ in the modem. When running in 3-wire serial mode, flow control should be turned ‘off’, which will ensure you get responses to your requests.

Use the command AT&K0 at the start of your command sequence. This turns flow control off and should solve the problem.

How to control the sleep pin

The sleep signal is internally pulled high on the RockBLOCK and RocKBLOCK Plus products, so you can leave it disconnected if you want to leave the modem ‘awake’ all of the time.

To turn ‘off’ the modem, pull the line to ground.

Do you have USB drivers for my XYZ platform?

Almost certainly. If you have purchased the optional FTDI-USB adaptor, you’ll need to install the FTDI drivers. You can check on their website (, where you’ll find drivers for Linux, Mac, Windows, Android and others.

What about software?

The RockBLOCK appears as a serial interface, and you can talk to it using a simple set of AT commands. It is expected that you’ll be able to integrate it into your own software with minimal effort.

Could you give us some sample code to get started?

There is a Node.js library available and an Arduino library which you can get via the developer docs. There’s also an excellent Python project for Raspberry Pi, which would make a great starting point for any Raspberry Pi users which can be found at We’re working on publishing some samples for other languages soon.

How do my messages get back to me (on Earth)?

Messages sent from RockBLOCK can either be delivered to your chosen email address or sent to your own web service as a simple HTTP POST. The message data will be hex encoded so there are no character set problems. Full details of our web service are available in the web service guide.

How do I send data to my RockBLOCK?

You can make a simple HTTP POST to our web service. The message is queued on the satellite network almost instantly, ready for RockBLOCK to download (on your command).

Does RockBLOCK get notification of a new message waiting?

Yes, as long as you configure it correctly. Check the documentation for the ‘Ring Alert’ feature.

Do I get positions with my messages?

The RockBLOCK does not have a GPS chip inside it. It’s envisaged that if you want position reports, you would use an off-the-shelf GPS module with your solution and get position data from that.

However, it’s worth noting that with each Iridium transmission we do get an approximate position report. This varies in accuracy from 100km to 1km, and therefore can’t be relied upon for accurate tracking, but we do provide this information for you (along with the approximate accuracy, ‘CEP’ in km) with your messages. If you’re looking for a dedicated tracking satellite tracking device, you might want to consider our RockSTAR, RockFLEET, or RockAIR products.

If I have a whole set of RockBLOCKs, how does billing work?

Our billing is flexible, and allows you to pay only when you’re using your devices. Line rental is sold in one-month blocks and credits are bought in packs. If you have several RockBLOCKs, credits are shared from a credit pool amongst all your devices. You don’t need to buy separate packs of credits for each device. Similarly, if only some of your devices are being used at any one time, you don’t need to pay for line rental on those which aren’t in use.

We also offer annual contracts for larger device deployments. Find out more about RockBLOCK airtime here.

Do you know what you're doing?

Yes. Ground Control has been an Iridium Partner since 2008. We’ve developed all sorts of products, from RockBLOCKs through to the MCD-MissionLINK case-based satellite internet solution, and we’re also the people behind YB Tracking.

"For us, the key benefit of the RockBLOCK 9603 is reliability. We don’t need to worry about what’s over the horizon – we know we’ll be able to communicate with our drones. It’s an essential part of our dual-redundancy system, and has never let us down."

Toby Moores, CEO Skylift


We're here to help

Get in touch with us and find out if the RockBLOCK 9603 is the right device for your needs. Either complete the form or call / email us to be directly connected with one of our satellite IoT experts.

With over 20 years experience in satellite tracking we have the knowledge and experience to ensure you are equipped with everything you need to make the right choice.
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