Brother MFC-7300C manual About Fax Machines, Fax Tones and Handshake, ECM Error Correction Mode

About Fax Machines

If you’re a first-time fax machine user, fax operation might seem a little mysterious. Soon, you’ll recognize the unusual fax tones on your phone line, and be able to send and receive faxes easily.

Fax Tones and Handshake

When someone is sending a fax, the MFC sends fax calling tones, (CNG tones)—soft, intermittent beeps at 4-second intervals. You’ll hear them when you dial and press Start, and they continue for about 40 seconds after dialing. During that time, the sending machine must begin the “handshake” with the receiving machine. Each time you use automatic procedures to send a fax, you are sending CNG tones over the phone line. You’ll soon learn to listen for these soft beeps each time you answer a phone on your MFC line, so you can know if you are receiving a fax message.

The receiving fax responds with fax receiving tones—loud, chirping sounds. A receiving fax chirps for about 40 seconds over the phone line, and the screen displays RECEIVE. 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 40 seconds, and the screen continues to display RECEIVE.

When your MFC answers in FAX/TEL mode, the MFC 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 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 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.

Note When you have an external telephone answering device (TAD) on your MFC 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 MFC.

ECM (Error Correction Mode)

The 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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