The internal revenue code imposes a 3% excise tax on revenues from communications services.  There are many things included in the definition of communications services that wouldn't be obvious and others that would appear to apply and don't.  The review of services that should have the excise tax applied to them can be complex and not always have black and white answers.  It can be important to review some of these questions with your tax advisers to avoid overbilling excise taxes on your services.
 

Excise Tax Summary