# Using the RockBLOCK Iridium Modem

## Overview

![](https://cdn-learn.adafruit.com/assets/assets/000/089/586/medium800thumb/sensors_Iridium_Coverage_Animation.jpg?1584638220)

Who's got the best coverage map? Anyone using the [Iridium satellite constellation](https://en.wikipedia.org/wiki/Iridium_satellite_constellation), that's who. How does **whole Earth** coverage sound? Summit of K2 to summit of Everest? Check. South pole to North pole? Super check. In the animated image above, red is good. Check that coverage at the poles!

So how do you use the Iridium satellites? Similar to cellphones, you need to purchase both hardware and service, and there are various options out there. In this guide we will show you how to setup and use the [Ground Control](http://www.groundcontrol.com/) [RockBLOCK 9603](https://www.groundcontrol.com/product/rockblock-9603-compact-plug-and-play-satellite-transmitter/) Iridium Satellite Modem. This hardware is tied to service that is also provided by [Ground Control](http://www.groundcontrol.com/).

We also have a [CircuitPython](https://circuitpython.org/) library that provides an easy way to transmit messages from any [CircuitPython board](https://circuitpython.org/downloads) with an available UART.

## Parts
- [Next Page](https://learn.adafruit.com/using-the-rockblock-iridium-modem/system-overview.md)

## Featured Products

### RockBLOCK 9603 with USB Cable - Iridium Satellite Modem Bundle

[RockBLOCK 9603 with USB Cable - Iridium Satellite Modem Bundle](https://www.adafruit.com/product/4521)
The **RockBLOCK 9603** allows you to send and receive short messages from anywhere on Earth with a clear view of the sky. And when we say anywhere we mean **anywhere**. It works far beyond the reach of WiFi and GSM networks. Maybe you want to transmit weather...

No Longer Stocked
[Buy Now](https://www.adafruit.com/product/4521)
[Related Guides to the Product](https://learn.adafruit.com/products/4521/guides)
### RockBLOCK 9603 Accessory Cable

[RockBLOCK 9603 Accessory Cable](https://www.adafruit.com/product/4529)
The **RockBLOCK 9603 Accessory Cable** is terminated with a simple 10-pin Molex-style connector at one end and male jumper wires at the other.

This accessory cable will help speed up your development time, meaning you no longer need to terminate and crimp your own connector...

No Longer Stocked
[Buy Now](https://www.adafruit.com/product/4529)
[Related Guides to the Product](https://learn.adafruit.com/products/4529/guides)

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