Ecm (Error Correction Mode) - Brother MFC-9800 Owner's Manual

The receiving fax responds with fax receiving tones—loud, chirping sounds. A
receiving fax chirps for about 60 seconds over the phone line, and the LCD
shows RECEIVING. If your MFC is set to the FAX mode, it will answer every
call automatically with fax receiving tones. Even if the other party hangs up,
your MFC continues to send the "chirps" for about 60 seconds, and the screen
continues to show RECEIVING.
The fax "handshake" is the time in which the sending machine's CNG tones and
the receiving machines "chirps" overlap. This must be for at least 2 to 4 seconds,
so the fax machines can understand how each is sending and receiving the fax.
The handshake cannot begin until the call is answered, and the CNG tones last
for only about 60 seconds after the number is dialed. Therefore, it's important
for the receiving MFC to answer the call in as few rings as possible.
When you have an external telephone answering device (TAD) on your fax
line, your TAD will determine the number of rings before the call is
answered. Pay special attention to the directions for connecting a TAD to your
MFC in Chapter 2, .
Assembly and Connections

ECM (Error Correction Mode)

ECM is a way for the MFC to check the integrity of a fax transmission while it
is in progress. ECM transmissions are possible only between machines that both
have the ECM feature. If they do, you may send and receive fax messages that
are continuously checked for their integrity. Sufficient memory must be
available in your MFC for this feature to work.
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