In universal personal telecommunications service, the UPT number (universal personal telecommunications number) uniquely identifies a UPT user and that is used to place a call to, or to forward a call to, that user.

A user may have multiple UPT numbers (e.g. a business UPT number for business calls and a private UPT number for private calls). In the case of multiple numbers, each UPT number is considered, from a network vantage point, to identify a distinct UPT user, even if all such numbers identify the same person or entity.

Source: from Federal Standard 1037C