§  4.7   Definitions of metrics used to determine the general outage-reporting
threshold criteria.

   (a) Administrative numbers are defined as the telephone numbers used by
   communications providers to perform internal administrative or
   operational functions necessary to maintain reasonable quality of
   service standards.

   (b) Assigned numbers are defined as the telephone numbers working in
   the Public Switched Telephone Network under an agreement such as a
   contract or tariff at the request of specific end users or customers
   for their use. This excludes numbers that are not yet working but have
   a service order pending.

   (c) Assigned telephone number minutes are defined as the mathematical
   result of multiplying the duration of an outage, expressed in minutes,
   by the sum of the number of assigned numbers (defined in paragraph (b)
   of this section) potentially affected by the outage and the number of
   administrative numbers (defined in paragraph (a) of this section)
   potentially affected by the outage. "Assigned telephone number minutes"
   can alternatively be calculated as the mathematical result of
   multiplying the duration of an outage, expressed in minutes, by the
   number of working telephone numbers potentially affected by the outage,
   where working telephone numbers are defined as the telephone numbers,
   including DID numbers, working immediately prior to the outage.

   (d) Optical Carrier 3 (OC3) minutes are defined as the mathematical
   result of multiplying the duration of an outage, expressed in minutes,
   by the number of previously operating OC3 circuits or their equivalents
   that were affected by the outage.

   (e) User minutes are defined as:

   (1) Assigned telephone number minutes (as defined in paragraph (c) of
   this section), for telephony, including non-mobile interconnected VoIP
   telephony, and for those paging networks in which each individual user
   is assigned a telephone number;

   (2) The mathematical result of multiplying the duration of an outage,
   expressed in minutes, by the number of end users potentially affected
   by the outage, for all other forms of communications. For
   interconnected VoIP service providers to mobile users, the number of
   potentially affected users should be determined by multiplying the
   simultaneous call capacity of the affected equipment by a concentration
   ratio of 8.

   (f) Working telephone numbers are defined to be the sum of all
   telephone numbers that can originate, or terminate telecommunications.
   This includes, for example, all working telephone numbers on the
   customer's side of a PBX, or Centrex, or similar arrangement.

   [ 69 FR 70338 , Dec. 3, 2004, as amended at  77 FR 25097 , Apr. 27, 2012;
    81 FR 45068 , July 12, 2016]