Common Questions

How do I get a RockBLOCK account?

If you have purchased a RockBLOCK, there will be paperwork inside the box which will have your login and password. If this paper is missing, or you have lost it, then please get in touch. You can register for an account at

I can't register my RockBLOCKs

It is possible that you are trying to register a device that has already been registered to another account. Please contact us, and include the serial number of IMEI of your RockBLOCKs so that we can look into the issue.

I have a whole set of RockBLOCKs. How does billing work?

Our billing is flexible, and allows you to pay only when you are using your devices. Line rental is sold in one-month blocks, and credits are bought in packs. 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.

What happens when line rental expires?

If your device's line rental expires, you can't sent/receive data until you renew its line rental - even if you have credits.

Can I activate line rental later and use my existing credits?

Of course! You'll need to use a minimum of one credit per year to retain your pool of credits. Otherwise, they will be lost.

How can I change my user name?

You'll need to contact us with your request using the email you've registered with.

How can I transfer ownership to another account?

You'll need to send a request from the email you've registered with, assigning your RockBLOCK(s) to someone else's account. Please include the serial numbers or IMEIs of the devices you'd like to transfer, as well as the account email that they will be transferred to.

I'd like to top-up with credits now and automatically activate line-rental from my device in an emergency.

Unfortunately, this isn't possible - if the RockBLOCK it doesn't have both credits line-rental, it can't communicate with us automatically. In an emergency, the account holder will need to purchase line rental and about 7-8 minutes later, the device will be ready to use.

Do RockBLOCKs have a GPS? How do I get accurate location/velocity data?

The RockBLOCK does not have a GPS chip inside it. If you want accurate position/velocity data, you would use an off-the-shelf GPS module with your solution.

However, it is worth noting that with each Iridium transmission we do get an approximate position report - this varies in accuracy from 1km to 200km and therefore cannot be relied upon for very accurate tracking. We do provide this information for you, along with the approximate position accuracy, 'CEP' (measured in km) with your messages.

If you are looking for a dedicated tracking satellite tracking device that includes GPS, then you might want to consider our RockSTAR product.


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?

If the device is turned on, you should be able to complete an Iridium SBD session roughly every 10 seconds, assuming a perfect view of the sky.

Does RockBLOCK get notification of a new message waiting?

Yes, as long as you configure it correctly. Check out the Ring Alerts chapter for more information. Your RockBLOCK must be turned on, with a clear line-of-sight with the sky in order to be able to receive ring alerts.

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 can I remove all messages in the MT queue that are waiting to be downloaded?

See the Receive data chapter for information on removing both ASCII and Binary messages in the MT queue.

I'd like to increase my chances of receiving a ring alert but worry I might be out of range.

RIng alerts are sent to the position of the last known SBDRT transmission. If you're moving quickly (for instance, as in an airplane), you can enable SBDREG. This automatically re-registers your tracker to receive ring alerts in your new position. For more information on the SBDREG command check out Iridium's AT Command Reference Manual..



An Iridium satellite spot beam is about 250 miles (400km) in diameter - this means your units can travel quite far before needing to re-register, and an SBD registration will only use up 1 credit.

Can I control RockBLOCKs via SMS?

This functionality isn't available natively. You could certainly build a system to receive SMS messages on your servers, and then use the Rock Seven API to control the systems, but this would be something you would need to create.


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.

Do you have USB drivers for my XYZ platform?

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

Could you give us some sample code to get started?

Please see the Further reading chapter for more information.

Unit refuses to give me data using the SBDRT command

If you are using the SBDRT command, and the modem appears to 'hang' when you issue the command, it is probably due to flow control configuration. The default state for the RockBLOCK and RockBLOCK+ 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.

I'm using IridiumSBD library and not transmitting.

There are many reasons for the unit not being able to transmit. The main reason is that it does not have a good view of the sky. However, in your transcript you should always see the SBDIX command being issued (which is the command which asks the modem to 'try' to transmit).

If you are using the IridiumSBD library ( by Mikal Hart) and you are not seeing this command appear in your transcript, then your unit is not even attempting to transmit data. It's possible that you are being affected a hangover from a previous firmware issue on Iridium devices.

To counter this add the line:


after the line:


This appears to resolve the problem in most cases, and you should start seeing the SBDIX command being shown in your transcripts.

I'm experiencing problems talking to the RockBLOCK using Arduino Mega.

If you are using the library 'IridiumSBD', you may experience some issues talking to the RockBLOCK, depending how you have set things up. The problem is, the IridiumSBD module uses 'SoftwareSerial', and you can't use SoftwareSerial on all the pins on the Mega. See for details. Happily, the solution is an easy one. Change the RX pin to one that supports pin change interrupts. Also (and this is just as important), make sure you haven't got your TX and RX lines mixed up. This is VERY easy to do, depending which way you think you are viewing TX/RX from, the RockBLOCK or the Arduino. If it doesn't work one way around, try the other way!


Will RockBLOCK work in space / on a CubeSat?

We don't know. This question comes up quite often, and we think lots of people have tried, or are intending to try integrating a RockBLOCK into a CubeSat. There are likely problems caused by the speed of the CubeSat, relative to the Iridium satellites.

I need to have accurate UTC time for years to come - but the Iridium epoch might change. Is there a reliable way of getting UTC time without worrying about what epoch we're in?

Iridium epochs's have changed twice and it'll be a while until any possible change in the future. Nevertheless, you can:

  • Allow for some sort of command to be sent to your unit, which provides an epoch offset - therefore you could update your devices in the field for new Iridium epochs in future.
  • Add a GPS unit to your device, and thus you could query that every so often if you can't achieve the first option.