From usenet: 900 Series Prefix to OCN translation table Please note that this differs from the 800 table, because much fewer of the 900 NXXs are assigned. NXX OCN NXX OCN NXX OCN NXX OCN NXX OCN 200 ATX 202 Ameritech 210 ATX 220 ATX 221 TDX 222 ONC 223 TDX 225 Pac. Bell 226 MCI 233 TDX 234 TEN 240 U.S. West 248 Ameritech 250 ATX 258 TEN 254 TTU 255 SNT 260 ATX 264 ADG 266 CSY 272 Bell Atl. 273 CAN 275 ITT 280 Ameritech 282 LGT 283 Pac. Bell 288 GTE N.west 297 CAN 300 ATX 301 Ameritech 302 Ameritech 303 Pac. Bell 321 TEN 322 TDX 327 ETS 328 ATX 331 TET 332 PLG 333 U.S. West 335 Bell Atl. 342 ATX 344 ATX 345 ALN 346 United Tel.350 ATX 364 GTE N.west 366 ONC 369 TEN 370 ATX 377 GTS 386 United Tel.388 SNT 399 ARZ 400 ATX 407 ATX 410 ATX 420 ATX 422 ALN 426 PLG 428 Ameritech 430 U.S. West 444 ONC 445 PHE 446 MCI 450 Ameritech 451 CAN 456 TEN 463 United Tel.478 AAM 479 ARZ 480 ATX 483 GTE Midwest488 ONC 490 U.S. West 500 ATX 505 Pac. Bell 520 ATX 529 MIT 536 BUR 540 ALN 543 ALN 545 GTE Calif. 550 ALN 555 ATX 567 ALN 580 U.S. West 590 ATX ÿ595 CAN 600 ATX 620 Ameritech 624 Pac. Bell 626 CSY 628 Ameritech 630 CAN 633 MIT 639 PLG 643 CAN 645 CAN 650 ATX 654 TEN 656 SNT 660 ATX 661 United Tel.663 MDE 665 ALN 666 ONC 670 CAN 677 CAN 678 MCI 680 ATX 686 LTG 690 CAN 698 NY Tel. 699 PLG 701 Bell Atl. 710 TGN 720 ATX 722 Pac. Bell 724 RTC 725 SNT 727 GTE Calif. 730 ATX 739 CSY 740 ATX 741 TEN 746 ITT 750 CAN 753 ALN 765 ALN 773 ATX 777 Pac. Bell 778 Ameritech 780 Ameritech 786 ATX 790 CAN 792 CAN 801 Bell Atl. 820 ATX 830 CAN 843 Pac. Bell 844 Pac. Bell 847 United Tel.850 ATX 860 ATX 866 AAM 870 CAN 872 TEN 887 ETS 888 CIS 900 TDX 901 Bell Atl. 903 ATX 909 ATX 924 Ameritech 932 ATX 948 ARZ 949 MIC 963 TEN 970 MIC 971 MIC 972 MIC 973 MIC 974 ALN 975 ALN 976 ATX 988 MCI 990 MCI 991 ALG 993 SNT 999 TEN