posted on Jun, 15 2007 @ 02:55 PM
Back in the day a neat trick with motorola 9122 "brick" phones was to ground pin 7 and hold down a couple of keys to enter debug mode. From there
you could unmute the speaker, set it to receive, and scan all the cell freqs in the area, listening in on conversations, and basically turning it into
a scanner. If you wanted to listen in on a call someone was making you'd set up the phone to scan, and just keep incrementing channels till you
recognized the voice or call content.
You could buy a scanner and a DTMF decoder from several different sources, put the two together, and decode all the keypresses, stealing a mailbox
password. With a bit of extra effort, you could also get ESN/NAM info to display as well as keyprsses if you can have the scanner catch the first
bits of data sent.
I haven't had a cellphone for years, so there's probably a different method for digital gsm or whatever they use now, but i'd be willing to bet
it'd still be do-able with off the shelf hardware and a bit of patience.