This is the White Star Balloon Comm Controller Software for Arduino. 

REQUIRES the library WSWire: http://github.com/whitestarballoon/WSWireLib
Do not use with the stock Arduino 1.0 Wire Library, or it will freeze in some I2C situations.

Current hardware:
Arduino Mega

Modem that will be connected as a shield will be the Iridium 9602.

Arduino Mega Pin connections:
0  
1  
2  SAT Ring Indicator (RI)
3  SAT Network Available
4  SAT Power Enable (On/Off)
5  SAT 3.3V Supply Enable
6  SAT DSR (rises on boot complete)
7  

8  
9  
10 
11 
12 
13 

14 UART3 ET2 RX-OUT
15 UART3 ET2 TX-IN
16 UART2 ET1 RX-OUT - Cutdown
17 UART2 ET1 TX-IN - Cutdown
18 @UART1 SAT Serial TXO
19 @UART1 SAT Serial RXI
20 @WSBCOMMSHIELD I2C SCL
21 @WSBCOMMSHIELD I2C SDA

A00 WSBCOMMSHIELD 
A01 WSBCOMMSHIELD 
A02 - 
A03 -
A04 WSBCOMMSHIELD I2C SDA
A05 WSBCOMMSHIELD I2C SCL
A06 -
A07 -
A08 -
A09 -
A10 WSBCOMMSHIELD I2C SCL
A11 WSBCOMMSHIELD I2C SDA