Fax Tones And Handshake; Ecm (Error Correction Mode) - Brother MFC-7420 User Manual

Fax tones and handshake

When someone is sending a fax, the fax
machine sends fax calling tones (CNG
tones). These are quiet, intermittent beeps
every 4-seconds. You'll hear them after you
dial and press Start and they will continue for
about 60 seconds after dialing. During that
time, the sending machine must begin the
"handshake" or connection with the receiving
machine.
Each time you use automatic procedures to
send a fax, you are sending CNG tones over
the phone line. You will soon learn to listen for
these quiet beeps each time you answer a
phone on your fax line, so you will know if you
are receiving a fax message.
The receiving fax responds with fax receiving
tones, which are loud, chirping sounds. A
receiving fax chirps for about 40 seconds
over the phone line, and the LCD shows
Receiving .
If your MFC is set to the Fax Only mode, it will
answer every call automatically with fax
receiving tones. If the other person hangs up,
your MFC will continue to send the "chirps" for
about 40 seconds, and the LCD continues to
show Receiving . To cancel receiving, press
Stop/Exit.
The fax 'handshake' is the time in which the
sending machine's CNG tones and the
receiving machine's "chirps" overlap. This
must be for at least 2 to 4 seconds, so both
machines can understand how each is
sending and receiving the fax. The
handshake cannot begin until the call is
answered, and the CNG tones only last for
about 60 seconds after the number is dialed.
So it is important for the receiving machine to
answer the call in as few rings as possible.

ECM (Error Correction Mode)

The Error Correction Mode (ECM) is a way for
the MFC to check a fax transmission while it
is in progress. If the MFC detects errors
during fax transmission, it resends the pages
of the fax that had an error. ECM
transmissions are only possible between fax
machines that both have this feature. If they
do, you may send and receive fax messages
that are continuously being checked by the
MFC.
If this feature stops working, delete your
faxes from the memory.
Introduction
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