T.37
（重定向自IFax）
T.37 is an ITU standard which deals with sending fax messages using email. It is also referred to as "iFax", "Internet Fax", or "Store-forward-fax".
A fax machine supporting T.37 will send a fax to an email address by converting the document to a TIFF-F image, attaching it to an email (using the MIME format), and sending the document (using SMTP). The destination fax receives the email and prints the attached document.