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It wasn't explained how the crims got the pin number after he entered them into his phone. I assume because each number on the keypad has a unique tone, they c
by jasey 13y ago
It wasn't explained how the crims got the pin number after he entered them into his phone.
I assume because each number on the keypad has a unique tone, they could extrapolate which keys were pressed?
Also how did they get his phone number? The phone directory?
Most shocking is how did they get date of birth and mothers maiden name!?!?
- matthiasl 13y agoAbout the PIN: your guess is right. The tone system for dialling numbers works like this: there are four "low" frequencies (697, 770, 852, 941 Hz) and four "high" frequencies (1209, 1336, 1477, 1633 Hz). Each key plays exactly one "low" and one "high" frequency, e.g. when you press "1", your phone plays 697 and 1209 Hz. The telephone exchange listens for those tone combinations to know what number you're dialling. If you have an audio recording of a number being dialled, you can actually figure out the number just by listening to each tone separately and comparing it to the sound made by pressing keys on your own phone. Wouldn't surprise me if the fraudsters did just that, or maybe they used a "spectrum analysis" feature on a PC audio program.
- sophacles 13y agoThere are programs that will do this for you... probably even for your smartphone. I mean - it is built into asterisk and other pbx software already, code for it can't be that hard to find.
- robmcm 13y agoSomeone suggested they went through his rubbish once they were standing out side his house. Seems like a bit of a gamble though as by this point they would have invested quite a bit of time following him etc. And how many people these days (young and living in a shared house in Islington especially) still have a land line, and are even in the phone book?