TUCoPS :: Phreaking Caller ID
:: russ-aon.wav
AONs (Automatical Number Identifiers).
This signal is most interesting of all. When you pick up
the receiver of the ringing phone you can hear beautiful
chord in the first 500 milliseconds. It is a 7- digit
number of the calling party represented by CCITT tones
without silence between the tones. If you have a
microprocessor-equipped phone it can decode tones and show
the calling party number on a LCD display. In some cases
the phone must send a short 500 Hz request tone before the
CO equipment plays the chord. In fact this signal was
designed for identification of the calling party by the
toll office. But advanced amateurs guessed how to use this
feature in the first self-made computerized phones in the
middle 1980's. Those phones, called AONs (automatical
number identifiers), was spread first among the computer
underground. Later they filled a black market, and only
lasted a few years before the Telcos officially permitted
to use AONs.
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