With a DVB/Radio link to the network one could listen to transactions only to their address. You could think of bitcoin operated gas stations, bitcoin network-hubs in rural areas, micropayments to car-charging stations (all you need is power and a cheap DVB receiver to listen to the address "beacon" for a payment.
Now sending back transactions to the network is not covered, but can be done by using SMS or a small radio link to a local node. A bitcoin transaction is only about 64 bytes (!) so even a DTMF call or SMS should work fine.
A transaction send would look like this (normal TXid, in hex)
Now sending back transactions to the network is not covered, but can be done by using SMS or a small radio link to a local node. A bitcoin transaction is only about 64 bytes (!) so even a DTMF call or SMS should work fine.
A transaction send would look like this (normal TXid, in hex)
That would be in DTMF. Would take about 15 seconds to complete (http://www.audiocheck.net/audiocheck_dtmf.php)