A fax demodulator is a device used to intercept fax messages by listening in on a
telephone line
A telephone line or telephone circuit (or just line or circuit industrywide) is a single-user circuit on a telephone communication system. It is designed to reproduce speech of a quality that is understandable. It is the physical wire or oth ...
or radio signal.
Function
A typical (
Group III) fax transmission requires a two-way conversation between two
modem
The Democratic Movement (, ; MoDem ) is a centre to centre-right political party in France, whose main ideological trends are liberalism and Christian democracy, and that is characterised by a strong pro-Europeanist stance. MoDem was establis ...
s (that is, each participant must both transmit and receive).
Each modem may be part of a “fax machine” incorporating an
image scanner
An image scanner (often abbreviated to just scanner) is a device that optically scans images, printed text, handwriting, or an object and converts it to a digital image. The most common type of scanner used in the home and the office is the flatbe ...
and a printer.
Application
A
demodulator
Demodulation is the process of extracting the original information-bearing signal from a carrier wave. A demodulator is an electronic circuit (or computer program in a software-defined radio) that is used to recover the information content from ...
can only be used to observe a conversation between two fax modems, usually to record the image transmitted.
It cannot be used to receive a fax transmission in the usual sense, because a sending modem cannot transmit an image without first negotiating a connection with a receiving modem.
See also
*
Alfa DiskFax
References
External links
Faxing Solutions
Communication circuits
Fax
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