Editing FidoNet (section)

===Zone mail hour===
Since computer bulletin boards historically used the same [[telephone line]]s for transferring mail as were used for dial-in human users of the BBS, FidoNet policy dictates that at least one designated line of each FidoNet node must be available for accepting mail from other FidoNet nodes during a particular hour of each day.{{sfn|Schuyler|1992|loc=Section 6.0}}

''Zone Mail Hour'', as it was named, varies depending on the geographic location of the node, and was designated to occur during the early morning.  The exact hour varies depending on the time zone, and any node with only one telephone line is required to reject human callers. In practice, particularly in later times, most FidoNet systems tend to accept mail at any time of day when the phone line is not busy, usually during night.