Ecm (Error Correction Mode) - Brother FAX 2750 Owner's Manual

3
I N T R O D U C T I O N
When your fax machine answers in FAX/TEL mode, it listens for CNG
tones and then responds with receiving tones.
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 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 40 seconds after the number is dialed. Therefore, it's
important for the receiving machine 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 in the Installation chapter for
connecting a TAD to your fax machine.

ECM (Error Correction Mode)

The Error Correction Mode (ECM) is a way for the fax machine 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 fax machine for this feature to
work.