Telephones are much like the postal service. In general, telephones are hardly different at all from speaking face to face, and in general there is little special treatment required to handle them. But I do mention them because of the nuisance issues that the law has had to deal with with regard to telemarketers, scammers, and other people abusing the medium for personal gain. We will find the principles inherent in the laws laid down for telephones useful in some other similar circumstances later, most notably the issues surrounding "forced" communication, such as e-mail spam.
We can go ahead and roll fax machines into this category too; their biggest impact on the law was also a "forced communication" issue, where junk spams could cost the recipient money for toner and paper. As such it is very similar to normal telephones, when it comes to the legal issues.