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 Fax Start and they will continue for about 60 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 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 RECEIVE.

If the fax machine is set to the FAX ONLY mode, it will answer every call automatically with fax receiving tones. If the other person hangs up, the fax machine will continue to send the “chirps” for about 40 seconds, and the LCD continues to show RECEIVE. To cancel the receiving, press Stop/Exit.

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 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.

When you have an external Telephone Answering Device (TAD) on your fax line, your TAD will decide the number of rings before the call is answered. Pay special attention to the directions for connecting a TAD in this chapter. (See Connecting an external telephone answering device (TAD) on page 1-9.)

ECM (Error Correction Mode)

The Error Correction Mode (ECM) is a way for the fax machine to check a fax transmission while it is in progress. ECM transmissions are only possible between machines that both have this feature. If they do, you may send and receive fax messages that are continuously being checked by the machine.

The fax machine must have enough memory for this feature to work.

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