FAX EAVESDROPPING TECHNICIAL DATA FOR
By: firstname.lastname@example.org (EuroForce)
EDITORIAL NOTE: Fax monitoring is illegal except by permission. This
information is being provided as technical information for countermeasures
On the basis that I do not know your technical skill level, I will try to
explain the mechanism involved in the Fax recording task. In order to replay
a "fax-analogue" recording a few things
have to happen:
When you record a "fax-encoded" signal it is important that you
use a ultra stable dual track audio recorder, which has the automatic gain
- Step 1- Your recording equipment:
- Use Track 1:
- As your "Fax-encoded" audio track, monitoring the audio
- very carefully.
- Use Track 2:
- Record a 1200 Hz(US) 1000 Hz(Europe) square wave signal
- from a crystal source.
- Step 2- Your replay equipment:
- Playback your "fax-encoded" audio signal; in a phase lock
- circuit, comparing the 1200Hz reference signal against a stable
- 1200Hz external crystal source.
- Step 3- The small black box:
- Go to your local library, or call Rockwell in the US and call their
- applications engineer for a data sheet and application note on
- their fax/modem encoder chips. Their is a mod which enables
- you to decode, without using handshaking.
But you will STILL need an ultra stable recording source, also a digital
recording might still be possible.
We have written some firmware, which enables a Motorola 68000 chip to decode
previously encoded "fax-signals".
This patented firmware and associated circuits, have not been released for
Wishing you Good Luck with your work, I hope it helps.
EuroForce Investigations Ltd.
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