Test numbers for 8XX SPNs

source: Mark J Cuccia
  
250-0500 to 250-0549  AT&T
250-0550 to 250-0599  MCI
250-0600 to 250-0649  Sprint Long Distance
250-0650 to 250-0669  Sprint United/Centel
250-0670 to 250-0679  BellSouth
250-0700 to 250-0719  Pacific Bell
250-0720 to 250-0749  GTE
250-0750 to 250-0769  C&W Long Distance
250-0770 to 250-0799  Bell Atlantic
250-0800 to 250-0849  AT&T-Canada
250-0850 to 250-0869  Southwestern Bell
250-0870 to 250-0899  US West
250-0900 to 250-0919  Bellcore SCP
250-0920 to 250-0949  Ameritech
250-0950 to 250-0969  CBT / Ameritech
250-0970 to 250-0999  SNET
250-1000 to 250-1029  (NYNEX)
250-1030 to 250-1049  (unassigned)
250-1050 to 250-1053  Ameritech
250-1054 to 250-1057  Bell Atlantic
250-1058 to 250-1061  BellSouth
250-1062 to 250-1065  GTE
250-1066 to 250-1069  (NYNEX)
250-1070 to 250-1073  Pacific Bell
250-1074 to 250-1077  Southwestern Bell
250-1078 to 250-1081  SNET
250-1082 to 250-1085  Sprint United/Centel
250-1086 to 250-1089  US West
250-1090 to 250-1092  Bellcore SCP
250-1093 to 250-1098  Pacific Bell
250-1100 to 250-1225  Stentor (Canada)
   

Additional Information
 The LECs have test numbers, as they maintain the originating databases for translations from their originating area, and LECs can also provide inTRA-LATA 'only' toll-free 800/888/877/etc. numbers.

I think that 250-0000 thru 250-0499 is a reserved block. Offhand, I don't know what numbers above 250-1226 are used for.

I'll have to do some digging to see if other major carriers/resellers have 250-xxxx test numbers (LCI, etc.)