ILLINOIS BELL TEL CO
334 prefixes in 312 · initial assignments from the NANPA CO code file, 09/17/2026
| NPA-NXX | Rate center | OCN | Assigned | Pooled |
|---|---|---|---|---|
| 312-692 | CHICGOZN01 | 9329 | — | Yes |
| 312-693 | CHICGOZN01 | 9329 | — | — |
| 312-694 | CHICGOZN01 | 9329 | — | Yes |
| 312-695 | CHICGOZN01 | 9329 | — | — |
| 312-696 | CHICGOZN01 | 9329 | — | Yes |
| 312-697 | CHICGOZN01 | 9329 | — | Yes |
| 312-701 | CHICGOZN01 | 9329 | — | Yes |
| 312-703 | CHICGOZN01 | 9329 | — | — |
| 312-704 | CHICGOZN01 | 9329 | — | — |
| 312-707 | CHICGOZN01 | 9329 | — | — |
| 312-710 | CHICGOZN01 | 9329 | — | — |
| 312-712 | CHICGOZN01 | 9329 | — | — |
| 312-714 | CHICGOZN01 | 9329 | — | Yes |
| 312-715 | CHICGOZN01 | 9329 | — | Yes |
| 312-716 | CHICGOZN01 | 9329 | — | — |
| 312-726 | CHICGOZN01 | 9329 | — | — |
| 312-727 | CHICGOZN01 | 9329 | — | — |
| 312-729 | CHICGOZN01 | 9329 | — | — |
| 312-732 | CHICGOZN01 | 9329 | — | — |
| 312-733 | CHICGOZN01 | 9329 | — | — |
| 312-737 | CHICGOZN01 | 9329 | — | — |
| 312-738 | CHICGOZN01 | 9329 | — | — |
| 312-739 | CHICGOZN01 | 9329 | — | — |
| 312-742 | CHICGOZN01 | 9329 | — | — |
| 312-743 | CHICGOZN01 | 9329 | 2001-11-15 | Yes |
| 312-744 | CHICGOZN01 | 9329 | — | — |
| 312-745 | CHICGOZN01 | 9329 | — | — |
| 312-746 | CHICGOZN01 | 9329 | — | — |
| 312-747 | CHICGOZN01 | 9329 | — | — |
| 312-750 | CHICGOZN01 | 9329 | — | — |
| 312-751 | CHICGOZN01 | 9329 | — | — |
| 312-755 | CHICGOZN01 | 9329 | — | — |
| 312-756 | CHICGOZN01 | 9329 | — | Yes |
| 312-759 | CHICGOZN01 | 9329 | — | Yes |
| 312-762 | CHICGOZN01 | 9329 | — | — |
| 312-765 | CHICGOZN01 | 9329 | — | Yes |
| 312-770 | CHICGOZN01 | 9329 | — | Yes |
| 312-775 | CHICGOZN01 | 9329 | — | Yes |
| 312-781 | CHICGOZN01 | 9329 | — | — |
| 312-782 | CHICGOZN01 | 9329 | — | — |
| 312-786 | CHICGOZN01 | 9329 | — | — |
| 312-787 | CHICGOZN01 | 9329 | — | — |
| 312-788 | CHICGOZN01 | 9329 | — | Yes |
| 312-789 | CHICGOZN01 | 9329 | — | Yes |
| 312-790 | CHICGOZN01 | 9329 | — | — |
| 312-791 | CHICGOZN01 | 9329 | — | Yes |
| 312-793 | CHICGOZN01 | 9329 | — | — |
| 312-795 | CHICGOZN01 | 9329 | — | — |
| 312-797 | CHICGOZN01 | 9329 | — | — |
| 312-798 | CHICGOZN01 | 9329 | — | Yes |
| 312-799 | CHICGOZN01 | 9329 | — | Yes |
| 312-807 | CHICGOZN01 | 9329 | — | — |
| 312-808 | CHICGOZN01 | 9329 | — | — |
| 312-812 | CHICGOZN01 | 9329 | — | — |
| 312-814 | CHICGOZN01 | 9329 | — | — |
| 312-817 | CHICGOZN01 | 9329 | — | — |
| 312-819 | CHICGOZN01 | 9329 | — | — |
| 312-822 | CHICGOZN01 | 9329 | — | — |
| 312-823 | CHICGOZN01 | 9329 | — | Yes |
| 312-827 | CHICGOZN01 | 9329 | — | — |
| 312-828 | CHICGOZN01 | 9329 | — | — |
| 312-829 | CHICGOZN01 | 9329 | — | — |
| 312-831 | CHICGOZN01 | 9329 | — | — |
| 312-832 | CHICGOZN01 | 9329 | — | — |
| 312-834 | CHICGOZN01 | 9329 | — | Yes |
| 312-836 | CHICGOZN01 | 9329 | — | — |
| 312-840 | CHICGOZN01 | 9329 | — | — |
| 312-842 | CHICGOZN01 | 9329 | — | — |
| 312-845 | CHICGOZN01 | 9329 | — | — |
| 312-846 | CHICGOZN01 | 9329 | — | Yes |
| 312-849 | CHICGOZN01 | 9329 | — | — |
| 312-850 | CHICGOZN01 | 9329 | — | — |
| 312-853 | CHICGOZN01 | 9329 | — | — |
| 312-855 | CHICGOZN01 | 9329 | — | — |
| 312-856 | CHICGOZN01 | 9329 | — | Yes |
| 312-857 | CHICGOZN01 | 9329 | — | Yes |
| 312-861 | CHICGOZN01 | 9329 | — | — |
| 312-862 | CHICGOZN01 | 9329 | 2006-01-25 | Yes |
| 312-864 | CHICGOZN01 | 9329 | — | — |
| 312-867 | CHICGOZN01 | 9329 | — | — |
| 312-869 | CHICGOZN01 | 9329 | — | Yes |
| 312-875 | CHICGOZN01 | 9329 | — | — |
| 312-876 | CHICGOZN01 | 9329 | — | — |
| 312-879 | CHICGOZN01 | 9329 | — | Yes |
| 312-880 | CHICGOZN01 | 9329 | — | Yes |
| 312-886 | CHICGOZN01 | 9329 | — | — |
| 312-887 | CHICGOZN01 | 9329 | — | Yes |
| 312-899 | CHICGOZN01 | 9329 | — | Yes |
| 312-902 | CHICGOZN01 | 9329 | — | — |
| 312-904 | CHICGOZN01 | 9329 | — | — |
| 312-905 | CHICGOZN01 | 9329 | — | Yes |
| 312-906 | CHICGOZN01 | 9329 | — | Yes |
| 312-908 | CHICGOZN01 | 9329 | — | — |
| 312-912 | CHICGOZN01 | 9329 | — | Yes |
| 312-913 | CHICGOZN01 | 9329 | — | — |
| 312-915 | CHICGOZN01 | 9329 | — | — |
| 312-917 | CHICGOZN01 | 9329 | — | — |
| 312-920 | CHICGOZN01 | 9329 | — | — |
| 312-921 | CHICGOZN01 | 9329 | 2008-07-21 | Yes |
| 312-922 | CHICGOZN01 | 9329 | — | — |
These are initial assignees from NANPA CO-code records — because of number portability, the current serving carrier of individual numbers may differ. Bulk export requires a membership.