On an i9000 but the code to access the engineering menu (*#197328640# in Dialer) worked just the same – I’m assuming it’s standard across all recent Samsungs, not just the Galaxy S series.
Menu 1,8,3,1 displays the current ciphering status, i.e. whether or not your current call is currently encrypted.
"How to talk to the Modem with AT commands":
Any tips/ideas how to get this info would be great!
I suspect there will be several different way to get to this, but all may prove relevant...