Easily Recognizable NPA Codes
NPA Codes that due to their unique, recognizable digit pattern (i.e., common ‘B’ and ‘C’ digit) convey certain unique knowledge re: a call to a telephone number other than the number being dialed (e.g., 800+). ERCs may be sometimes referred to as NYY codes to signify that N = digits 2-9 and YY = repeating digits 0-9.