duplex fax

[JohnW12]

How can I set my device to duplex fax.  It's easy to duplex print and scan, but how can I duplex a fax?  Receiving and duplex printing is not a problem, but how can I duplex scan and fax a document?

[Repairatrooper · Accepted solution]

Not all models support duplex faxing through ADF. If that option exists then you would touch the fax menu when you first start the fax process, before dialing a number.

If there is no duplex option then you will have to send from the glass and turn the pages over manually. 

The reason for some features not being included is that if the receiving machine does not understand what a duplex page is it can cause a receiving error.

[JohnW12]

The answer I got from HP direct support was that this model (LaserJet Pro MFP M477fdw) cannot send duplex scanned documents.  It can print duplex upon receiving a fax, but cannot send using the duplex scanner included in the device.  The answer makes sense upon seeing the response from Repairatrooper that such a duplex fax could confuse the receiving fax machine.