Canon imageCLASS MF5750 Facsimile Manual page 79

Q Is the sending fax machine functioning properly?
A The sending fax machine usually determines the fax's quality. Call the sender
and have them make sure the scanning glass of their fax machine is clean.
Cannot receive a fax using ECM (Error Correction Mode).
Q Does the sending fax machine support ECM?
A If the sending fax machine does not support ECM, the document is received in
the normal mode without error checking.
Errors occur frequently while receiving.
Q Are the telephone lines in proper condition? Or do you have a good connection?
A Lower the reception speed. (See <4. RX START SPEED> of "Menu
Descriptions," on p. 8-2.)
Q Is the sending fax machine functioning properly?
A Call the sender and have them check that their fax machine is functioning
properly.
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Faxing Problems
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