Canon MX870 Series User Manual page 48

Change the number of seconds that the machine rings.
Set the machine to receive the fax after the machine stops ringing, even if you do not pick up
the handset.
See Settings for Receiving Faxes
When FAX only mode is selected:
When the call is a fax.
The machine will receive the fax automatically.
Note
If a telephone is connected to the machine, the telephone will ring when a call incomes.
When DRPD or Network switch is selected:
When the call is a fax:
The telephone will ring when a call incomes.
The machine will receive the fax automatically when the fax ring pattern is detected.
Note
Other options
Change the number of times to ring the telephone.
See
Settings for Receiving Faxes
When the call is a voice call:
The telephone will ring when a call incomes.
When the machine does not detect the fax ring pattern, the telephone will continue ringing.
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