All assignees
800 prefixes in 203 · initial assignments from the NANPA CO code file, 09/17/2026
| NPA-NXX | Rate center | OCN | Assigned | Pooled |
|---|---|---|---|---|
| 203-500 | NEW HAVEN | 4036 | 2001-10-25 | — |
| 203-501 | DANBURY | 6388 | 2010-07-09 | Yes |
| 203-502 | BRIDGEPORT | 9147 | — | Yes |
| 203-503 | NEW HAVEN | 9147 | — | Yes |
| 203-504 | STAMFORD | 829J | 2004-02-12 | Yes |
| 203-505 | NORWALK | 6388 | — | Yes |
| 203-506 | NEW HAVEN | 4036 | — | — |
| 203-507 | NEW HAVEN | 6624 | — | Yes |
| 203-508 | NEW HAVEN | 829J | 2005-02-03 | Yes |
| 203-509 | WATERBURY | 5562 | — | Yes |
| 203-510 | WATERBURY | 5562 | — | Yes |
| 203-511 | XXXXXXXXXX | MULT | — | — |
| 203-512 | DANBURY | 6624 | — | — |
| 203-513 | HUNTINGTON | 7421 | — | Yes |
| 203-514 | MERIDEN | 7143 | — | Yes |
| 203-515 | NORWALK | 6624 | — | Yes |
| 203-516 | ANSONIDRBY | 4800 | — | Yes |
| 203-517 | STAMFORD | 4800 | — | Yes |
| 203-518 | WATERBURY | 4036 | 2001-07-02 | Yes |
| 203-519 | WATERBURY | 5562 | 2011-02-09 | Yes |
| 203-520 | BRIDGEPORT | 6388 | 2002-05-30 | — |
| 203-521 | BRIDGEPORT | 6388 | — | — |
| 203-522 | BRIDGEPORT | 4036 | — | Yes |
| 203-523 | NORWALK | 7143 | — | Yes |
| 203-524 | STAMFORD | 4036 | — | Yes |
| 203-525 | WATERBURY | 4036 | — | — |
| 203-526 | BRIDGEPORT | 5562 | — | Yes |
| 203-527 | WATERBURY | 9147 | — | Yes |
| 203-528 | WATERBURY | 4800 | — | Yes |
| 203-529 | WILTON | 7421 | — | Yes |
| 203-530 | NEW HAVEN | 6388 | — | — |
| 203-531 | BYRAM | 9104 | — | — |
| 203-532 | BYRAM | 9104 | — | Yes |
| 203-533 | GUILFORD | 4800 | — | Yes |
| 203-534 | BRIDGEPORT | 9147 | — | Yes |
| 203-535 | NEW HAVEN | 318J | — | Yes |
| 203-536 | STAMFORD | 6388 | — | — |
| 203-537 | MERIDEN | 5562 | — | Yes |
| 203-538 | HUNTINGTON | 829J | — | Yes |
| 203-539 | STAMFORD | 9147 | — | Yes |
| 203-540 | BRIDGEPORT | 4036 | 2005-01-31 | Yes |
| 203-541 | STAMFORD | 9147 | — | Yes |
| 203-542 | GREENWICH | 7421 | — | Yes |
| 203-543 | BRIDGEPORT | 6624 | — | — |
| 203-544 | GEORGETOWN | 9147 | — | Yes |
| 203-545 | BRIDGEPORT | 5562 | — | Yes |
| 203-546 | DANBURY | 7143 | — | Yes |
| 203-547 | STAMFORD | 639C | — | — |
| 203-548 | STAMFORD | 4800 | 2002-05-30 | Yes |
| 203-549 | BRIDGEPORT | 829J | — | Yes |
| 203-550 | STAMFORD | 6624 | — | — |
| 203-551 | BRIDGEPORT | 7143 | — | Yes |
| 203-552 | BYRAM | 9104 | — | Yes |
| 203-553 | NEW HAVEN | 9147 | — | Yes |
| 203-554 | STAMFORD | 4036 | — | — |
| 203-555 | DIR ASST | MULT | — | — |
| 203-556 | BRIDGEPORT | 4036 | — | — |
| 203-557 | WESTPORT | 4950 | — | Yes |
| 203-558 | WATERBURY | 4036 | — | — |
| 203-559 | DARIEN | 7143 | — | Yes |
| 203-560 | WATERBURY | 4036 | — | — |
| 203-561 | STAMFORD | 6388 | — | — |
| 203-562 | NEW HAVEN | 9147 | — | — |
| 203-563 | WILTON | 9147 | — | Yes |
| 203-564 | STAMFORD | 7421 | — | Yes |
| 203-565 | WATERBURY | 5562 | — | Yes |
| 203-566 | STAMFORD | 7230 | 2003-02-04 | Yes |
| 203-567 | HUNTINGTON | 829J | — | Yes |
| 203-568 | WATERBURY | 829J | — | Yes |
| 203-569 | STAMFORD | 4950 | — | Yes |
| 203-570 | STAMFORD | 6624 | 2001-03-26 | — |
| 203-571 | WESTPORT | 7421 | — | Yes |
| 203-572 | BRIDGEPORT | 6624 | 2007-07-13 | Yes |
| 203-573 | WATERBURY | 9147 | — | — |
| 203-574 | WATERBURY | 9147 | — | — |
| 203-575 | WATERBURY | 9147 | — | — |
| 203-576 | BRIDGEPORT | 9147 | — | — |
| 203-577 | WATERBURY | 9147 | — | Yes |
| 203-578 | WATERBURY | 9147 | — | Yes |
| 203-579 | BRIDGEPORT | 9147 | — | — |
| 203-580 | BYRAM | 539F | 2012-10-02 | Yes |
| 203-581 | BRIDGEPORT | 9147 | — | Yes |
| 203-582 | NEW HAVEN | 9147 | — | — |
| 203-583 | BRIDGEPORT | 4800 | — | Yes |
| 203-584 | NEW HAVEN | 6388 | 2010-07-09 | Yes |
| 203-585 | STAMFORD | 9147 | — | Yes |
| 203-586 | WOODBURY | 7143 | — | Yes |
| 203-587 | GEORGETOWN | 612K | — | Yes |
| 203-588 | STAMFORD | 4950 | — | Yes |
| 203-589 | NEW HAVEN | 6624 | — | Yes |
| 203-590 | TRUMBULL | 4800 | 2011-03-18 | Yes |
| 203-591 | WATERBURY | 9147 | — | — |
| 203-592 | WATERBURY | 4036 | — | — |
| 203-593 | NORWALK | 6630 | — | — |
| 203-594 | NEW CANAAN | 4950 | — | Yes |
| 203-595 | STAMFORD | 9147 | — | Yes |
| 203-596 | WATERBURY | 9147 | — | — |
| 203-597 | WATERBURY | 9147 | — | Yes |
| 203-598 | WATERBURY | 9147 | — | Yes |
| 203-599 | MERIDEN | 4800 | — | Yes |
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.