Brother FAX 275 - Manual (Page 17)

3
I N T R O D U C T I O N
When your fax machine answers in FAX/TEL Mode, the fax machine 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.