Only power in and data in-out.
Wouldn't be surprised if they had some encrypted version of 4G or satellite as backup connectivity and make sure 100% uptime. The great thing about mining is that the bandwidth requirements should remain constant regardless of the size of hardware!
Speaking as someone that has suffered through both Sat and Cellular as a primary internet connection, there is no such thing as 100% uptime with those types of connection.
They're viable in a pinch as backup connectivity, as mining isn't data-intensive, but redundant links of REAL Internet connections (one DSL, one CableModem for example) would be a TON better on reliability.
When Iridium gets it's new constellation on line, they MIGHT be able to argue with DSL and Cable Modem on reliability (though not on speed) and be in the ballpark on lag, but any current Sat link is guarenteed to have well over a half SECOND of lag at best when it's working, and Cellular tends to have dropout issues a lot of the time unless you're right under a tower, and the towers themselves have reliability issues at times.
The bandwidth does NOT remain constant regardless of the size of the hardware - but it's low enough even a decent 3G cellular link should have enough bandwidth (except when updating the blockchain) to handle multiple Petahash when the link is up at all....
