 These cases hold that a telephonic communication for which there is a toll charge that varies with elapsed transmission time "and not distance" (time-only service) is not taxable toll telephone service as defined in §4252(b)(1) of the Internal Revenue Code.As a result, amounts paid for time-only service are not subject to the tax imposed by §4251.Accordingly, the government will no longer litigate this issue [...] [emphasis added]

The IRS also provided the following definitions in Notice 2006-50