Newsgroup: uk.telecom

From: (Diomidis Spinellis)
Newsgroups: uk.telecom
Subject: How to decode DTMF tones (was BT technology at fault on itemised bills)
Date: 21 Apr 1993 15:44:58 GMT
Organization: Dept. of Computing, Imperial College, University of London, UK.
Lines: 21
Message-ID: <>
References: <>
Content-Length: 807
>From article <>, by (Richard Cox):
> Not as many people have the ability to decode these tones, as one might
> think.  Nevertheless a loophole to be aware of.
How to decode DTMF tones:

1) Record the tones
2) Dial your friendly bank computerised access system
3) Login with your account and PIN
4) Give commands for a payment or transfer
5) Play back the tones
6) Press # to terminate the "ammount in pence"
7) Listen to the message asking you to verify the transaction which
   includes the numbers you played back.
8) Cancel the transaction
9) Hang up

Diomidis Spinellis    Internet: <>  UUCP: ...!uknet!icdoc!dds
Department of Computing, Imperial College, London SW7     #include "/dev/tty"

Newsgroup uk.telecom contents
Newsgroup list
Diomidis Spinellis home page

Creative Commons License Unless otherwise expressly stated, all original material on this page created by Diomidis Spinellis is licensed under a Creative Commons Attribution-Share Alike 3.0 Greece License.