An exchange of emails with the friend who has lent me his 3G USB modem revealed that there is no PIN number on the SIM. However, apparently these things can be a little awkward, and error messages can be obscure, especially when there is no 3G or GPRS signal.
Reassured that I’m not about to lock myself out of the network by getting the SIM PIN number wrong too many times in a row, I did a little debugging. The modem may be recognised as a USB device, but it most definitely is not recognised as a modem. A quick check on my kernel configuration parameters reveals that I’ve not included a couple of crucial drivers.
15 minutes recompiling and reinstalling my kernel, insert the USB stick, and Network Manager cuts in, and establishes a 3G connection to the Internet. It really was as simple as that.
So expect updates from my hospital bed in due course 🙂