Dont take the Tmobile map as gospel when I got a dongle to start with got told it would work fine in my postcode when I got it home turned ot to be worse than a dial up connection Took it back to the carphone warehouse who contacted Tmobile who then looked on another map on their system and came back and told me that it was in a 3G blackspot and they were not upgrading it. Got the contract cancelled there and then. Went with 3 instead which was better but did have problems with them as well
It depends on the dongle. Aparently the Huwei one used by 3 is a composite device, It is a modem and a memory device. When you plug it into a windows machne it installs a driver which tells the computer that it is not to be treated as a memory device and to switch on the modem. When you plug it into a linux machine it doesn't install any drivers as linux is not supported. The linux machine only sees the device as a memory device, the code I linked to is to tell the linux machine how to turn on the modem.