Black fax to harass large institutions or government departments, to retaliate against the senders of junk faxes, or merely as simple pranks. The basic principle of a black fax can be extended to form a "black fax attack." In this case, one or more sheets are fed halfway through the sender's fax machine and taped end to end, forming an endless loop that cycles through the machine. Not only can solid black be used, but also images which will repeat endlessly on the receiver's machine until its toner runs out. The introduction of computer-based facsimile systems (combined with integrated document imaging solutions)
Internet fax Not all fax equipment claiming T.38 compliance works reliably. In particular communicating with older fax machines is problematic. As with regular faxes, only one fax can be sent or received at a time. While the needs of computer-to-fax communications are well covered, the simplicity of quickly faxing a handwritten document combined with the advantages of email are not. "iFax" (T.37) was designed for fax machines to directly communicate via email. Faxes are sent as email attachments in a TIFF-F format. A new fax machine (supporting iFax/T.37) is required, as well as a known email address for the sending and receiving