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)
Fax modem faxing with a fax/modem declined at the turn of the century. Where faxing from a PC is required there are a number of Internet-based faxing alternatives. Where businesses still had one or more traditional fax machines churning out pages, they were usually outnumbered by PCs processing E-mail. Computer users may set up a PC fax/modem with card, telephone line access and software. A special printer driver may be included to allow treating a fax modem as a printer. Fax integration is available in unified communications ("e.g. E-mail, Voice Mail and Fax managed together"), in a number of Hosted PBX products