When sending or receiving a fax, documents that contain mostly text usually take approximately 1 minute per page. For documents that contain graphics (e.g. scans of documents), or for faxes that are being sent through a slow phone line, it may take 5 minutes per page or more to be sent or delivered.
It is important to note that unlike a mechanical fax machine, faxes are not sent or received one page at a time, they are sent as one complete documents. Therefore, you will get no indication of a document's progress until all pages are transmitted.