Fax tones and handshake; ECM (Error Correction Mode); Introduction- Page 33

Introduction

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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.