Modes Cannot Switch Automatically between Telephone and Fax

Is the machine set to automatically switch modes between telephone and fax?
NO
Set the receive mode to <Fax/Tel Auto Switch> or <Answering Machine>.
"Changing the Receive Mode"
When <Answering Machine> is set, make sure that an external telephone with the built-in answer function is connected to the machine. Also make sure that it is always turned on and the recorded answering message can be heard anytime.
YES
Is the time set for <Ring Start Time> too short?
YES
When you set the ring time too short, incoming faxes may be regarded as incoming phone calls. Set a longer ring time for incoming faxes in <Ring Start Time>.
"Advanced Settings for the Fax/Tel Auto Switch Mode"
NO
Is the line condition of the sender's machine good?
NO
Change the <RX Start Speed>.
"RX Start Speed"
YES
Is memory full?
YES
Print, send, or delete jobs stored in memory.
NO
Can the sender's machine send a switching signal, to notify your machine of an incoming fax?
NO
Some machines cannot send this signal. In this case, receive the fax manually.