Canon MX520 series Fax Manual page 36

Sending Faxes after Checking Information (Checking the Recipient's Information)
Set Check RX FAX information to ON following the procedure below.
Important
This function is not available when you send a fax manually.
Sending a Fax after Speaking on Telephone
1. Make sure that the machine is turned on.
Confirming that the Power Is On
2. Press the MENU button.
The menu screen is displayed.
3. Select Setup, then press the OK button.
4. Select Device settings, then press the OK button.
5. Use the button to select FAX settings, then press the OK button.
6. Use the button to select Security control, then press the OK button.
7. Use the button to select Check RX FAX information, then press the OK button.
8. Use the button to select ON, then press the OK button.
Important
Transmission will be canceled if the machine fails to receive the recipient's fax information or if
the received information does not match the fax/telephone number.