Verified Nov 1, 2026 · Source: NANPA CO Code Assignment Records
Area code 203 prefixes
784 of the 786 possible NXX blocks are assigned in area code 203 (99.7% of capacity), spread across 33 rate centers and 22 holders. The largest holders are SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT (338 blocks, 43.1%), CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CT (61 blocks, 7.8%), NEW CINGULAR WIRELESS PCS, LLC - DC (52 blocks, 6.6%). Grouped by brand, AT&T accounts for 437 blocks; brand-attributable holders cover 99% of the code, and the rest are CLECs, VoIP wholesalers and regional carriers that trade under their own names. The assignment records here run from 2001-01-03 to 2024-09-18, with 26 blocks handed out in 2001 alone. 473 blocks (60%) are in thousands-block pooling, meaning the block is shared between carriers in 1,000-number lots rather than held whole – which is why a single NXX can serve several carriers at once. 69 were growth assignments – additional blocks to a carrier that had already filled its earlier ones.
784 assigned blocks of 786
33 rate centers
22 holders of record
60% in thousands-block pooling
Largest holders in 203
| Holder of record, as NANPA names it | Brand | Blocks | Share |
|---|---|---|---|
| SOUTHERN NEW ENGLAND TELCO DBA FRONTIER COMM OF CT | AT&T | 338 | 43.1% |
| CELLCO PARTNERSHIP DBA VERIZON WIRELESS - CT | Verizon | 61 | 7.8% |
| NEW CINGULAR WIRELESS PCS, LLC - DC | AT&T | 52 | 6.6% |
| OMNIPOINT COMMUNICATIONS, INC. - CT | T-Mobile | 47 | 6% |
| LEVEL 3 COMMUNICATIONS, LLC - CT | Lumen | 41 | 5.2% |
| PAETEC ITEL, LLC | Windstream | 40 | 5.1% |
| MCIMETRO ACCESS TRANSMISSION SERVICES LLC - CT | Verizon | 37 | 4.7% |
| TELEPORT COMMUNICATIONS AMERICA, LLC - CT | AT&T | 33 | 4.2% |
| CABLEVISION LIGHTPATH, INC. - CT | Altice | 29 | 3.7% |
| METROPCS, INC. | T-Mobile | 25 | 3.2% |
| VERIZON NEW YORK, INC. | Verizon | 15 | 1.9% |
| AT&T - LOCAL | AT&T | 12 | 1.5% |
Names are printed as they appear in the assignment records, which is the legal entity rather than the brand. Holding a block is not the same as serving the numbers in it: portability moves numbers between carriers and pooling splits a block between several.
Rate centers with their own page
Rate centers where at least three blocks are assigned, excluding the numbered metro zone codes. The remainder are in the full table below.
NEW HAVEN 145STAMFORD 97BRIDGEPORT 94NORWALK 60DANBURY 54WATERBURY 52GREENWICH 27MERIDEN 24ANSONIDRBY 17WESTPORT 16DARIEN 15FAIRFIELD 15HUNTINGTON 14WALLINGFD 14MILFORD 14TRUMBULL 13BRANFORD 10CHESHIRE 10OLDGRNWICH 9NEW CANAAN 9GUILFORD 8WILTON 8WOODBURY 8BYRAM 8MADISON 6NAUGATUCK 6RIDGEFIELD 5NEWTOWN 5SEYMOUR 5WOLCOTT 4REDDING 3GEORGETOWN 3
All 784 assigned blocks
One row per NXX. “Pooled” means carriers draw 1,000-number lots from the block rather than holding all 10,000, so a pooled prefix can belong to several carriers at once. “Not in service” means assigned but not yet open for calls – a caller ID from one of those is necessarily spoofed. The holder column gives the brand where the legal entity maps to one; the full legal names are in the holders table above, exactly as NANPA records them.
| Prefix | Holder of record | Rate center | Assigned | Pooled | In service |
|---|---|---|---|---|---|
| 203-200 | Bandwidth | NEW HAVEN | 2008-08-14 | yes | yes |
| 203-201 | Spok | NEW HAVEN | – | – | yes |
| 203-202 | Altice | DARIEN | – | yes | yes |
| 203-203 | Onvoy | GREENWICH | 2024-09-18 | yes | yes |
| 203-204 | AT&T | GUILFORD | – | yes | yes |
| 203-205 | AT&T | DANBURY | – | yes | yes |
| 203-206 | AT&T | WATERBURY | – | – | yes |
| 203-207 | AT&T | DANBURY | – | yes | yes |
| 203-208 | Comcast | BRANFORD | – | yes | yes |
| 203-209 | Verizon | BRIDGEPORT | – | – | yes |
| 203-210 | Altice | WILTON | – | yes | yes |
| 203-212 | AT&T | BRIDGEPORT | 2008-10-23 | yes | yes |
| 203-213 | AT&T | MERIDEN | – | – | yes |
| 203-214 | AT&T | NEW HAVEN | – | – | yes |
| 203-215 | AT&T | NEW HAVEN | – | – | yes |
| 203-216 | AT&T | WESTPORT | – | yes | yes |
| 203-217 | AT&T | WATERBURY | – | – | yes |
| 203-218 | AT&T | BRIDGEPORT | – | – | yes |
| 203-219 | AT&T | STAMFORD | – | – | yes |
| 203-220 | Altice | TRUMBULL | – | yes | yes |
| 203-221 | AT&T | WESTPORT | – | – | yes |
| 203-222 | AT&T | WESTPORT | – | – | yes |
| 203-223 | T-Mobile | STAMFORD | – | yes | yes |
| 203-224 | AT&T | BRIDGEPORT | – | yes | yes |
| 203-225 | AT&T | HUNTINGTON | – | – | yes |
| 203-226 | AT&T | WESTPORT | – | – | yes |
| 203-227 | AT&T | WESTPORT | – | – | yes |
| 203-228 | Verizon | WATERBURY | 2002-10-04 | yes | yes |
| 203-229 | AT&T | NORWALK | – | – | yes |
| 203-230 | AT&T | NEW HAVEN | – | – | yes |
| 203-231 | Verizon | ANSONIDRBY | – | – | yes |
| 203-232 | Verizon | WATERBURY | – | – | yes |
| 203-233 | Verizon | WATERBURY | – | – | yes |
| 203-234 | AT&T | NEW HAVEN | – | – | yes |
| 203-235 | AT&T | MERIDEN | – | – | yes |
| 203-236 | AT&T | WATERBURY | – | – | yes |
| 203-237 | AT&T | MERIDEN | – | – | yes |
| 203-238 | AT&T | MERIDEN | – | – | yes |
| 203-239 | AT&T | NEW HAVEN | – | – | yes |
| 203-240 | Verizon | DANBURY | – | – | yes |
| 203-241 | Verizon | DANBURY | – | – | yes |
| 203-242 | Altice | HUNTINGTON | – | yes | yes |
| 203-243 | T-Mobile | BRIDGEPORT | – | – | yes |
| 203-244 | CSC VOICE, LLC | RIDGEFIELD | 2003-03-28 | yes | yes |
| 203-245 | AT&T | MADISON | – | – | yes |
| 203-246 | Verizon | NORWALK | – | yes | yes |
| 203-247 | Verizon | NORWALK | – | – | yes |
| 203-248 | AT&T | NEW HAVEN | – | – | yes |
| 203-249 | Verizon | STAMFORD | – | – | yes |
| 203-250 | AT&T | CHESHIRE | – | – | yes |
| 203-251 | AT&T | STAMFORD | – | – | yes |
| 203-252 | Altice | STAMFORD | – | yes | yes |
| 203-253 | Verizon | STAMFORD | – | – | yes |
| 203-254 | AT&T | FAIRFIELD | – | – | yes |
| 203-255 | AT&T | FAIRFIELD | – | – | yes |
| 203-256 | AT&T | FAIRFIELD | – | – | yes |
| 203-257 | Verizon | BRIDGEPORT | – | – | yes |
| 203-258 | Verizon | BRIDGEPORT | – | – | yes |
| 203-259 | AT&T | FAIRFIELD | – | – | yes |
| 203-260 | AT&T | BRIDGEPORT | – | – | yes |
| 203-261 | AT&T | TRUMBULL | – | – | yes |
| 203-262 | AT&T | WOODBURY | – | yes | yes |
| 203-263 | AT&T | WOODBURY | – | yes | yes |
| 203-264 | AT&T | WOODBURY | – | – | yes |
| 203-265 | AT&T | WALLINGFD | – | – | yes |
| 203-266 | AT&T | WOODBURY | – | yes | yes |
| 203-267 | AT&T | WOODBURY | – | yes | yes |
| 203-268 | AT&T | TRUMBULL | – | – | yes |
| 203-269 | AT&T | WALLINGFD | – | – | yes |
| 203-270 | AT&T | NEWTOWN | – | – | yes |
| 203-271 | AT&T | CHESHIRE | – | – | yes |
| 203-272 | AT&T | CHESHIRE | – | – | yes |
| 203-273 | Verizon | STAMFORD | 2002-10-22 | yes | yes |
| 203-274 | AT&T | STAMFORD | – | yes | yes |
| 203-275 | AT&T | BRIDGEPORT | – | yes | yes |
| 203-276 | Altice | STAMFORD | 2003-03-28 | yes | yes |
| 203-277 | Verizon | OLDGRNWICH | 2003-04-16 | yes | yes |
| 203-278 | T-Mobile | ANSONIDRBY | 2001-05-01 | yes | yes |
| 203-279 | Spok | BRIDGEPORT | – | – | yes |
| 203-280 | Verizon | DARIEN | 2004-03-24 | yes | yes |
| 203-281 | AT&T | NEW HAVEN | – | – | yes |
| 203-282 | Spok | STAMFORD | – | – | yes |
| 203-283 | Altice | MILFORD | – | yes | yes |
| 203-284 | AT&T | WALLINGFD | – | – | yes |
| 203-285 | AT&T | NEW HAVEN | – | yes | yes |
| 203-286 | Windstream | NORWALK | – | yes | yes |
| 203-287 | AT&T | NEW HAVEN | – | – | yes |
| 203-288 | AT&T | NEW HAVEN | – | – | yes |
| 203-289 | Spok | DANBURY | – | – | yes |
| 203-290 | T-Mobile | BRIDGEPORT | 2013-11-14 | yes | yes |
| 203-291 | AT&T | WESTPORT | – | yes | yes |
| 203-292 | Altice | FAIRFIELD | – | yes | yes |
| 203-293 | Verizon | WESTPORT | – | yes | yes |
| 203-294 | AT&T | WALLINGFD | – | – | yes |
| 203-295 | Verizon | NORWALK | – | yes | yes |
| 203-296 | Verizon | BRIDGEPORT | – | yes | yes |
| 203-297 | Verizon | DANBURY | – | yes | yes |
| 203-298 | Altice | NEW HAVEN | – | yes | yes |
| 203-299 | AT&T | NORWALK | – | yes | yes |
| 203-300 | T-Mobile | DANBURY | 2001-10-25 | yes | yes |
| 203-301 | AT&T | MILFORD | – | yes | yes |
| 203-302 | AT&T | GREENWICH | – | yes | yes |
| 203-303 | AT&T | WALLINGFD | – | yes | yes |
| 203-304 | AT&T | NEWTOWN | – | yes | yes |
| 203-305 | AT&T | ANSONIDRBY | – | – | yes |
| 203-306 | Windstream | MILFORD | – | yes | yes |
| 203-307 | Verizon | FAIRFIELD | 2005-01-31 | yes | yes |
| 203-308 | Verizon | ANSONIDRBY | 2008-10-22 | yes | yes |
| 203-309 | T-Mobile | DARIEN | 2007-09-11 | yes | yes |
| 203-310 | Verizon | NEW CANAAN | 2003-04-16 | yes | yes |
| 203-312 | AT&T | DANBURY | – | yes | yes |
| 203-313 | Verizon | DANBURY | – | yes | yes |
| 203-314 | Verizon | NEW HAVEN | – | – | yes |
| 203-315 | AT&T | BRANFORD | – | – | yes |
| 203-316 | AT&T | STAMFORD | – | – | yes |
| 203-317 | AT&T | MERIDEN | – | yes | yes |
| 203-318 | AT&T | MADISON | – | yes | yes |
| 203-319 | AT&T | FAIRFIELD | – | – | yes |
| 203-320 | Verizon | DARIEN | 2003-04-16 | yes | yes |
| 203-321 | AT&T | STAMFORD | – | yes | yes |
| 203-322 | AT&T | STAMFORD | – | – | yes |
| 203-323 | AT&T | STAMFORD | – | – | yes |
| 203-324 | AT&T | STAMFORD | – | – | yes |
| 203-325 | AT&T | STAMFORD | – | – | yes |
| 203-326 | AT&T | STAMFORD | – | yes | yes |
| 203-327 | AT&T | STAMFORD | – | yes | yes |
| 203-328 | AT&T | STAMFORD | – | – | yes |
| 203-329 | AT&T | STAMFORD | – | – | yes |
| 203-330 | AT&T | BRIDGEPORT | – | – | yes |
| 203-331 | AT&T | BRIDGEPORT | – | yes | yes |
| 203-332 | AT&T | BRIDGEPORT | – | – | yes |
| 203-333 | AT&T | BRIDGEPORT | – | – | yes |
| 203-334 | AT&T | BRIDGEPORT | – | – | yes |
| 203-335 | AT&T | BRIDGEPORT | – | – | yes |
| 203-336 | AT&T | BRIDGEPORT | – | – | yes |
| 203-337 | AT&T | BRIDGEPORT | – | – | yes |
| 203-338 | AT&T | BRIDGEPORT | – | yes | yes |
| 203-339 | AT&T | BRIDGEPORT | – | yes | yes |
| 203-340 | Altice | GREENWICH | 2003-08-19 | yes | yes |
| 203-341 | AT&T | WESTPORT | – | – | yes |
| 203-342 | Spok | BRIDGEPORT | – | – | yes |
| 203-343 | AT&T | ANSONIDRBY | 2012-01-18 | yes | yes |
| 203-344 | Altice | OLDGRNWICH | – | yes | yes |
| 203-345 | Altice | BRIDGEPORT | – | yes | yes |
| 203-346 | AT&T | WATERBURY | – | yes | yes |
| 203-347 | Lumen | BYRAM | 2004-03-11 | yes | yes |
| 203-348 | AT&T | STAMFORD | – | – | yes |
| 203-349 | AT&T | WESTPORT | – | yes | yes |
| 203-350 | AT&T | MADISON | – | yes | yes |
| 203-351 | AT&T | STAMFORD | – | – | yes |
| 203-352 | AT&T | STAMFORD | – | – | yes |
| 203-353 | AT&T | STAMFORD | – | – | yes |
| 203-354 | Altice | NORWALK | – | yes | yes |
| 203-355 | Altice | STAMFORD | – | – | yes |
| 203-356 | AT&T | STAMFORD | – | yes | yes |
| 203-357 | AT&T | STAMFORD | – | yes | yes |
| 203-358 | AT&T | STAMFORD | – | yes | yes |
| 203-359 | AT&T | STAMFORD | – | – | yes |
| 203-360 | T-Mobile | BRIDGEPORT | 2008-12-10 | yes | yes |
| 203-361 | Lumen | NEW HAVEN | 2010-12-16 | yes | yes |
| 203-362 | AT&T | BRIDGEPORT | – | yes | yes |
| 203-363 | AT&T | STAMFORD | – | yes | yes |
| 203-364 | AT&T | NEWTOWN | – | yes | yes |
| 203-365 | AT&T | BRIDGEPORT | – | – | yes |
| 203-366 | AT&T | BRIDGEPORT | – | – | yes |
| 203-367 | AT&T | BRIDGEPORT | – | – | yes |
| 203-368 | AT&T | BRIDGEPORT | – | yes | yes |
| 203-369 | Verizon | OLDGRNWICH | 2003-10-07 | yes | yes |
| 203-370 | American Messaging | NEW HAVEN | – | – | yes |
| 203-371 | AT&T | BRIDGEPORT | – | – | yes |
| 203-372 | AT&T | BRIDGEPORT | – | – | yes |
| 203-373 | AT&T | BRIDGEPORT | – | – | yes |
| 203-374 | AT&T | BRIDGEPORT | – | – | yes |
| 203-375 | AT&T | BRIDGEPORT | – | – | yes |
| 203-376 | Verizon | NEW HAVEN | – | – | yes |
| 203-377 | AT&T | BRIDGEPORT | – | – | yes |
| 203-378 | AT&T | BRIDGEPORT | – | – | yes |
| 203-379 | AT&T | MERIDEN | – | yes | yes |
| 203-380 | AT&T | BRIDGEPORT | – | – | yes |
| 203-381 | AT&T | BRIDGEPORT | – | – | yes |
| 203-382 | AT&T | BRIDGEPORT | – | yes | yes |
| 203-383 | AT&T | BRIDGEPORT | – | yes | yes |
| 203-384 | AT&T | BRIDGEPORT | – | – | yes |
| 203-385 | AT&T | BRIDGEPORT | – | yes | yes |
| 203-386 | AT&T | BRIDGEPORT | – | – | yes |
| 203-387 | AT&T | NEW HAVEN | – | – | yes |
| 203-388 | Verizon | STAMFORD | – | yes | yes |
| 203-389 | AT&T | NEW HAVEN | – | – | yes |
| 203-390 | AT&T | NEW HAVEN | 2015-11-10 | yes | yes |
| 203-391 | Verizon | STAMFORD | – | yes | yes |
| 203-392 | AT&T | NEW HAVEN | – | yes | yes |
| 203-393 | AT&T | NEW HAVEN | – | yes | yes |
| 203-394 | AT&T | BRIDGEPORT | – | yes | yes |
| 203-395 | T-Mobile | BRIDGEPORT | – | yes | yes |
| 203-396 | AT&T | BRIDGEPORT | – | – | yes |
| 203-397 | AT&T | NEW HAVEN | – | yes | yes |
| 203-398 | Spok | NORWALK | – | – | yes |
| 203-399 | Verizon | STAMFORD | – | yes | yes |
| 203-400 | AT&T | TRUMBULL | 2002-02-19 | yes | yes |
| 203-401 | AT&T | NEW HAVEN | – | yes | yes |
| 203-402 | AT&T | HUNTINGTON | – | yes | yes |
| 203-403 | AT&T | RIDGEFIELD | – | yes | yes |
| 203-404 | Lumen | NEW HAVEN | – | yes | yes |
| 203-405 | Windstream | WOODBURY | 2001-04-04 | yes | yes |
| 203-406 | AT&T | STAMFORD | – | yes | yes |
| 203-407 | AT&T | NEW HAVEN | – | yes | yes |
| 203-408 | Bandwidth | REDDING | – | yes | yes |
| 203-409 | AT&T | OLDGRNWICH | – | yes | yes |
| 203-410 | T-Mobile | NEW HAVEN | – | yes | yes |
| 203-412 | American Messaging | NEW HAVEN | – | – | yes |
| 203-413 | Windstream | GREENWICH | – | – | yes |
| 203-414 | AT&T | BRIDGEPORT | – | – | yes |
| 203-415 | AT&T | NEW HAVEN | 2001-04-12 | – | yes |
| 203-416 | AT&T | BRIDGEPORT | – | yes | yes |
| 203-417 | AT&T | DANBURY | – | – | yes |
| 203-418 | AT&T | FAIRFIELD | – | yes | yes |
| 203-419 | AT&T | WATERBURY | – | yes | yes |
| 203-420 | AT&T | MERIDEN | – | – | yes |
| 203-421 | AT&T | MADISON | – | yes | yes |
| 203-422 | Verizon | GREENWICH | – | yes | yes |
| 203-423 | AT&T | WILTON | – | yes | yes |
| 203-424 | T-Mobile | DARIEN | 2007-06-29 | yes | yes |
| 203-425 | AT&T | STAMFORD | – | – | yes |
| 203-426 | AT&T | NEWTOWN | – | – | yes |
| 203-427 | Verizon | MERIDEN | – | yes | yes |
| 203-428 | Verizon | STAMFORD | – | yes | yes |
| 203-429 | Verizon | WESTPORT | – | yes | yes |
| 203-430 | AT&T | NEW HAVEN | – | – | yes |
| 203-431 | AT&T | RIDGEFIELD | – | – | yes |
| 203-432 | Bandwidth | NEW HAVEN | – | – | yes |
| 203-433 | Comcast | BRANFORD | – | yes | yes |
| 203-434 | T-Mobile | NORWALK | – | – | yes |
| 203-435 | T-Mobile | NEW HAVEN | – | – | yes |
| 203-436 | AT&T | NEW HAVEN | – | – | yes |
| 203-437 | Verizon | WATERBURY | – | yes | yes |
| 203-438 | AT&T | RIDGEFIELD | – | – | yes |
| 203-439 | Comcast | CHESHIRE | – | yes | yes |
| 203-440 | Comcast | MERIDEN | – | yes | yes |
| 203-441 | AT&T | WOLCOTT | – | yes | yes |
| 203-442 | AT&T | NEW CANAAN | – | yes | yes |
| 203-443 | Verizon | MERIDEN | – | yes | yes |
| 203-444 | AT&T | NEW HAVEN | – | – | yes |
| 203-445 | AT&T | TRUMBULL | – | yes | yes |
| 203-446 | AT&T | ANSONIDRBY | – | yes | yes |
| 203-447 | AT&T | HUNTINGTON | – | yes | yes |
| 203-448 | Verizon | DANBURY | – | yes | yes |
| 203-449 | T-Mobile | BRIDGEPORT | – | yes | yes |
| 203-450 | Verizon | BRIDGEPORT | 2008-05-12 | yes | yes |
| 203-451 | AT&T | WESTPORT | – | – | yes |
| 203-452 | AT&T | TRUMBULL | – | – | yes |
| 203-453 | AT&T | GUILFORD | – | – | yes |
| 203-454 | AT&T | WESTPORT | – | – | yes |
| 203-455 | Verizon | BRIDGEPORT | – | yes | yes |
| 203-456 | Verizon | DANBURY | 2011-12-06 | yes | yes |
| 203-457 | AT&T | GUILFORD | – | yes | yes |
| 203-458 | AT&T | GUILFORD | – | – | yes |
| 203-459 | AT&T | TRUMBULL | – | – | yes |
| 203-460 | T-Mobile | DANBURY | – | yes | yes |
| 203-461 | AT&T | STAMFORD | – | yes | yes |
| 203-462 | AT&T | STAMFORD | – | – | yes |
| 203-463 | AT&T | SEYMOUR | – | yes | yes |
| 203-464 | Verizon | NEW HAVEN | – | – | yes |
| 203-465 | AT&T | WATERBURY | – | yes | yes |
| 203-466 | AT&T | NEW HAVEN | – | yes | yes |
| 203-467 | AT&T | NEW HAVEN | – | – | yes |
| 203-468 | AT&T | NEW HAVEN | – | – | yes |
| 203-469 | AT&T | NEW HAVEN | – | – | yes |
| 203-470 | Verizon | DANBURY | – | – | yes |
| 203-471 | AT&T | XXXXXXXXXX | – | – | yes |
| 203-472 | AT&T | XXXXXXXXXX | – | – | yes |
| 203-473 | AT&T | XXXXXXXXXX | – | – | yes |
| 203-474 | AT&T | XXXXXXXXXX | – | – | yes |
| 203-476 | AT&T | XXXXXXXXXX | – | – | yes |
| 203-477 | Spok | NEW HAVEN | – | – | yes |
| 203-478 | AT&T | XXXXXXXXXX | – | – | yes |
| 203-479 | AT&T | NEW HAVEN | – | yes | yes |
| 203-480 | Verizon | FAIRFIELD | – | yes | yes |
| 203-481 | AT&T | BRANFORD | – | – | yes |
| 203-482 | AT&T | DANBURY | 2001-03-23 | yes | yes |
| 203-483 | AT&T | BRANFORD | – | – | yes |
| 203-484 | AT&T | BRANFORD | – | yes | yes |
| 203-485 | Altice | GREENWICH | – | yes | yes |
| 203-486 | AT&T | WOODBURY | – | yes | yes |
| 203-487 | Lumen | STAMFORD | 2001-01-03 | yes | yes |
| 203-488 | AT&T | BRANFORD | – | – | yes |
| 203-489 | Altice | GREENWICH | 2011-05-25 | yes | yes |
| 203-490 | AT&T | NAUGATUCK | – | yes | yes |
| 203-491 | Bandwidth | NEWTOWN | 2010-02-12 | yes | yes |
| 203-492 | AT&T | NEW HAVEN | – | yes | yes |
| 203-493 | Lumen | GEORGETOWN | – | yes | yes |
| 203-494 | Verizon | NEW HAVEN | – | – | yes |
| 203-495 | AT&T | NEW HAVEN | – | – | yes |
| 203-496 | T-Mobile | GREENWICH | – | yes | yes |
| 203-497 | AT&T | NEW HAVEN | – | yes | yes |
| 203-498 | AT&T | NEW HAVEN | – | – | yes |
| 203-499 | AT&T | NEW HAVEN | – | yes | yes |
| 203-500 | AT&T | NEW HAVEN | 2001-10-25 | – | yes |
| 203-501 | Verizon | DANBURY | 2010-07-09 | yes | yes |
| 203-502 | AT&T | BRIDGEPORT | – | yes | yes |
| 203-503 | AT&T | NEW HAVEN | – | yes | yes |
| 203-504 | Windstream | STAMFORD | 2004-02-12 | yes | yes |
| 203-505 | Verizon | NORWALK | – | yes | yes |
| 203-506 | AT&T | NEW HAVEN | – | – | yes |
| 203-507 | T-Mobile | NEW HAVEN | – | yes | yes |
| 203-508 | Windstream | NEW HAVEN | 2005-02-03 | yes | yes |
| 203-509 | T-Mobile | WATERBURY | – | yes | yes |
| 203-510 | T-Mobile | WATERBURY | – | yes | yes |
| 203-512 | T-Mobile | DANBURY | – | – | yes |
| 203-513 | AT&T | HUNTINGTON | – | yes | yes |
| 203-514 | AT&T | MERIDEN | – | yes | yes |
| 203-515 | T-Mobile | NORWALK | – | yes | yes |
| 203-516 | Lumen | ANSONIDRBY | – | yes | yes |
| 203-517 | Lumen | STAMFORD | – | yes | yes |
| 203-518 | AT&T | WATERBURY | 2001-07-02 | yes | yes |
| 203-519 | T-Mobile | WATERBURY | 2011-02-09 | yes | yes |
| 203-520 | Verizon | BRIDGEPORT | 2002-05-30 | – | yes |
| 203-521 | Verizon | BRIDGEPORT | – | – | yes |
| 203-522 | AT&T | BRIDGEPORT | – | yes | yes |
| 203-523 | AT&T | NORWALK | – | yes | yes |
| 203-524 | AT&T | STAMFORD | – | yes | yes |
| 203-525 | AT&T | WATERBURY | – | – | yes |
| 203-526 | T-Mobile | BRIDGEPORT | – | yes | yes |
| 203-527 | AT&T | WATERBURY | – | yes | yes |
| 203-528 | Lumen | WATERBURY | – | yes | yes |
| 203-529 | AT&T | WILTON | – | yes | yes |
| 203-530 | Verizon | NEW HAVEN | – | – | yes |
| 203-531 | Verizon | BYRAM | – | – | yes |
| 203-532 | Verizon | BYRAM | – | yes | yes |
| 203-533 | Lumen | GUILFORD | – | yes | yes |
| 203-534 | AT&T | BRIDGEPORT | – | yes | yes |
| 203-535 | Comcast | NEW HAVEN | – | yes | yes |
| 203-536 | Verizon | STAMFORD | – | – | yes |
| 203-537 | T-Mobile | MERIDEN | – | yes | yes |
| 203-538 | Windstream | HUNTINGTON | – | yes | yes |
| 203-539 | AT&T | STAMFORD | – | yes | yes |
| 203-540 | AT&T | BRIDGEPORT | 2005-01-31 | yes | yes |
| 203-541 | AT&T | STAMFORD | – | yes | yes |
| 203-542 | AT&T | GREENWICH | – | yes | yes |
| 203-543 | T-Mobile | BRIDGEPORT | – | – | yes |
| 203-544 | AT&T | GEORGETOWN | – | yes | yes |
| 203-545 | T-Mobile | BRIDGEPORT | – | yes | yes |
| 203-546 | AT&T | DANBURY | – | yes | yes |
| 203-547 | Onvoy | STAMFORD | – | – | yes |
| 203-548 | Lumen | STAMFORD | 2002-05-30 | yes | yes |
| 203-549 | Windstream | BRIDGEPORT | – | yes | yes |
| 203-550 | T-Mobile | STAMFORD | – | – | yes |
| 203-551 | AT&T | BRIDGEPORT | – | yes | yes |
| 203-552 | Verizon | BYRAM | – | yes | yes |
| 203-553 | AT&T | NEW HAVEN | – | yes | yes |
| 203-554 | AT&T | STAMFORD | – | – | yes |
| 203-556 | AT&T | BRIDGEPORT | – | – | yes |
| 203-557 | Altice | WESTPORT | – | yes | yes |
| 203-558 | AT&T | WATERBURY | – | – | yes |
| 203-559 | AT&T | DARIEN | – | yes | yes |
| 203-560 | AT&T | WATERBURY | – | – | yes |
| 203-561 | Verizon | STAMFORD | – | – | yes |
| 203-562 | AT&T | NEW HAVEN | – | – | yes |
| 203-563 | AT&T | WILTON | – | yes | yes |
| 203-564 | AT&T | STAMFORD | – | yes | yes |
| 203-565 | T-Mobile | WATERBURY | – | yes | yes |
| 203-566 | Verizon | STAMFORD | 2003-02-04 | yes | yes |
| 203-567 | Windstream | HUNTINGTON | – | yes | yes |
| 203-568 | Windstream | WATERBURY | – | yes | yes |
| 203-569 | Altice | STAMFORD | – | yes | yes |
| 203-570 | T-Mobile | STAMFORD | 2001-03-26 | – | yes |
| 203-571 | AT&T | WESTPORT | – | yes | yes |
| 203-572 | T-Mobile | BRIDGEPORT | 2007-07-13 | yes | yes |
| 203-573 | AT&T | WATERBURY | – | – | yes |
| 203-574 | AT&T | WATERBURY | – | – | yes |
| 203-575 | AT&T | WATERBURY | – | – | yes |
| 203-576 | AT&T | BRIDGEPORT | – | – | yes |
| 203-577 | AT&T | WATERBURY | – | yes | yes |
| 203-578 | AT&T | WATERBURY | – | yes | yes |
| 203-579 | AT&T | BRIDGEPORT | – | – | yes |
| 203-580 | Peerless | BYRAM | 2012-10-02 | yes | yes |
| 203-581 | AT&T | BRIDGEPORT | – | yes | yes |
| 203-582 | AT&T | NEW HAVEN | – | – | yes |
| 203-583 | Lumen | BRIDGEPORT | – | yes | yes |
| 203-584 | Verizon | NEW HAVEN | 2010-07-09 | yes | yes |
| 203-585 | AT&T | STAMFORD | – | yes | yes |
| 203-586 | AT&T | WOODBURY | – | yes | yes |
| 203-587 | CSC VOICE, LLC | GEORGETOWN | – | yes | yes |
| 203-588 | Altice | STAMFORD | – | yes | yes |
| 203-589 | T-Mobile | NEW HAVEN | – | yes | yes |
| 203-590 | Lumen | TRUMBULL | 2011-03-18 | yes | yes |
| 203-591 | AT&T | WATERBURY | – | – | yes |
| 203-592 | AT&T | WATERBURY | – | – | yes |
| 203-593 | Spok | NORWALK | – | – | yes |
| 203-594 | Altice | NEW CANAAN | – | yes | yes |
| 203-595 | AT&T | STAMFORD | – | yes | yes |
| 203-596 | AT&T | WATERBURY | – | – | yes |
| 203-597 | AT&T | WATERBURY | – | yes | yes |
| 203-598 | AT&T | WATERBURY | – | yes | yes |
| 203-599 | Lumen | MERIDEN | – | yes | yes |
| 203-600 | T-Mobile | MERIDEN | 2008-10-03 | yes | yes |
| 203-601 | AT&T | TRUMBULL | – | yes | yes |
| 203-602 | AT&T | STAMFORD | – | yes | yes |
| 203-603 | AT&T | NEW HAVEN | – | – | yes |
| 203-604 | Lumen | NORWALK | 2001-03-14 | yes | yes |
| 203-605 | Verizon | NEW HAVEN | – | – | yes |
| 203-606 | T-Mobile | NEW HAVEN | – | – | yes |
| 203-607 | Verizon | STAMFORD | 2003-02-04 | yes | yes |
| 203-608 | Windstream | MERIDEN | – | yes | yes |
| 203-609 | AT&T | STAMFORD | – | yes | yes |
| 203-610 | Windstream | BRIDGEPORT | – | yes | yes |
| 203-612 | Lumen | BRIDGEPORT | – | yes | yes |
| 203-613 | T-Mobile | NORWALK | – | yes | yes |
| 203-614 | AT&T | STAMFORD | – | yes | yes |
| 203-615 | AT&T | BRIDGEPORT | – | yes | yes |
| 203-616 | Lumen | DANBURY | – | yes | yes |
| 203-617 | T-Mobile | DANBURY | 2006-09-05 | yes | yes |
| 203-618 | Verizon | GREENWICH | – | – | yes |
| 203-619 | AT&T | NEW HAVEN | – | yes | yes |
| 203-620 | Verizon | DARIEN | 2004-07-19 | yes | yes |
| 203-621 | Windstream | DARIEN | – | yes | yes |
| 203-622 | Verizon | GREENWICH | – | – | yes |
| 203-623 | Verizon | NEW HAVEN | – | – | yes |
| 203-624 | AT&T | NEW HAVEN | – | – | yes |
| 203-625 | Verizon | GREENWICH | – | yes | yes |
| 203-626 | AT&T | WALLINGFD | – | yes | yes |
| 203-627 | T-Mobile | NEW HAVEN | – | yes | yes |
| 203-628 | Altice | DANBURY | – | yes | yes |
| 203-629 | Verizon | GREENWICH | – | – | yes |
| 203-630 | AT&T | MERIDEN | – | – | yes |
| 203-631 | AT&T | MERIDEN | – | – | yes |
| 203-632 | Windstream | NAUGATUCK | – | yes | yes |
| 203-633 | Lumen | WOLCOTT | – | yes | yes |
| 203-634 | AT&T | MERIDEN | – | – | yes |
| 203-635 | Lumen | WESTPORT | – | yes | yes |
| 203-636 | Verizon | DARIEN | 2004-09-14 | yes | yes |
| 203-637 | AT&T | OLDGRNWICH | – | – | yes |
| 203-638 | Windstream | TRUMBULL | – | yes | yes |
| 203-639 | AT&T | MERIDEN | – | – | yes |
| 203-640 | AT&T | NEW HAVEN | – | – | yes |
| 203-641 | Verizon | NEW HAVEN | – | – | yes |
| 203-642 | Verizon | NORWALK | – | yes | yes |
| 203-643 | Windstream | BRANFORD | – | yes | yes |
| 203-644 | Verizon | NORWALK | – | yes | yes |
| 203-645 | AT&T | NEW HAVEN | – | – | yes |
| 203-646 | Onvoy | BRANFORD | – | yes | yes |
| 203-647 | Windstream | MILFORD | – | – | yes |
| 203-648 | Lumen | DANBURY | – | yes | yes |
| 203-649 | Windstream | CHESHIRE | – | yes | yes |
| 203-650 | T-Mobile | BRIDGEPORT | 2001-03-26 | yes | yes |
| 203-651 | Windstream | CHESHIRE | – | yes | yes |
| 203-652 | Windstream | NEW CANAAN | – | yes | yes |
| 203-653 | Windstream | STAMFORD | – | yes | yes |
| 203-654 | AT&T | NEW HAVEN | – | yes | yes |
| 203-655 | AT&T | DARIEN | – | – | yes |
| 203-656 | AT&T | DARIEN | – | – | yes |
| 203-657 | American Messaging | NEW HAVEN | – | – | yes |
| 203-658 | AT&T | STAMFORD | – | yes | yes |
| 203-659 | Windstream | FAIRFIELD | – | yes | yes |
| 203-660 | Onvoy | BYRAM | 2001-01-03 | yes | yes |
| 203-661 | Verizon | GREENWICH | – | – | yes |
| 203-662 | AT&T | DARIEN | – | – | yes |
| 203-663 | Windstream | NORWALK | – | yes | yes |
| 203-664 | CSC VOICE, LLC | REDDING | – | yes | yes |
| 203-665 | Windstream | WILTON | – | yes | yes |
| 203-666 | Lumen | BRIDGEPORT | 2013-09-26 | yes | yes |
| 203-667 | T-Mobile | STAMFORD | – | yes | yes |
| 203-668 | T-Mobile | NEW HAVEN | – | yes | yes |
| 203-669 | Lumen | DARIEN | – | yes | yes |
| 203-670 | T-Mobile | FAIRFIELD | 2021-12-06 | yes | yes |
| 203-671 | Verizon | NEW HAVEN | – | – | yes |
| 203-672 | Windstream | NEW HAVEN | – | – | yes |
| 203-673 | AT&T | BRIDGEPORT | – | yes | yes |
| 203-674 | AT&T | STAMFORD | – | yes | yes |
| 203-675 | T-Mobile | NEW HAVEN | – | yes | yes |
| 203-676 | T-Mobile | NEW HAVEN | – | yes | yes |
| 203-677 | AT&T | WALLINGFD | – | yes | yes |
| 203-678 | Windstream | WALLINGFD | – | yes | yes |
| 203-679 | AT&T | WALLINGFD | – | yes | yes |
| 203-680 | AT&T | NEW HAVEN | 2012-10-31 | yes | yes |
| 203-681 | Verizon | BYRAM | – | yes | yes |
| 203-682 | Windstream | WESTPORT | – | yes | yes |
| 203-683 | Windstream | BRIDGEPORT | – | yes | yes |
| 203-684 | T-Mobile | NEW HAVEN | 2008-10-03 | yes | yes |
| 203-685 | T-Mobile | BRIDGEPORT | 2001-03-30 | – | yes |
| 203-686 | AT&T | MERIDEN | – | – | yes |
| 203-687 | Lumen | NEW HAVEN | – | yes | yes |
| 203-688 | AT&T | NEW HAVEN | – | – | yes |
| 203-689 | AT&T | GUILFORD | – | yes | yes |
| 203-690 | T-Mobile | BRIDGEPORT | 2008-03-21 | yes | yes |
| 203-691 | AT&T | NEW HAVEN | – | yes | yes |
| 203-692 | Lumen | FAIRFIELD | – | yes | yes |
| 203-693 | Altice | MILFORD | 2010-07-13 | yes | yes |
| 203-694 | AT&T | MERIDEN | – | yes | yes |
| 203-695 | AT&T | WATERBURY | – | yes | yes |
| 203-696 | AT&T | BRIDGEPORT | – | – | yes |
| 203-697 | AT&T | WALLINGFD | – | yes | yes |
| 203-698 | AT&T | OLDGRNWICH | – | yes | yes |
| 203-699 | AT&T | CHESHIRE | – | yes | yes |
| 203-701 | AT&T | MILFORD | – | yes | yes |
| 203-702 | Windstream | DANBURY | – | yes | yes |
| 203-703 | AT&T | STAMFORD | – | yes | yes |
| 203-704 | Lumen | WOLCOTT | 2002-07-17 | yes | yes |
| 203-705 | Verizon | STAMFORD | – | yes | yes |
| 203-706 | Windstream | WATERBURY | 2004-02-12 | yes | yes |
| 203-707 | Verizon | WATERBURY | 2011-03-10 | yes | yes |
| 203-708 | AT&T | STAMFORD | – | yes | yes |
| 203-709 | AT&T | WATERBURY | – | yes | yes |
| 203-710 | AT&T | NEW HAVEN | – | – | yes |
| 203-712 | Lumen | HUNTINGTON | – | yes | yes |
| 203-713 | Onvoy | MILFORD | – | yes | yes |
| 203-714 | Charter | NAUGATUCK | – | yes | yes |
| 203-715 | T-Mobile | MERIDEN | – | yes | yes |
| 203-716 | Lumen | NEW CANAAN | – | yes | yes |
| 203-717 | CSC VOICE, LLC | GREENWICH | 2011-01-28 | yes | yes |
| 203-718 | Lumen | CHESHIRE | – | yes | yes |
| 203-719 | Verizon | STAMFORD | – | – | yes |
| 203-720 | AT&T | NAUGATUCK | – | yes | yes |
| 203-721 | Verizon | WATERBURY | – | yes | yes |
| 203-722 | AT&T | NORWALK | – | – | yes |
| 203-723 | AT&T | NAUGATUCK | – | yes | yes |
| 203-724 | Windstream | STAMFORD | – | yes | yes |
| 203-725 | Comcast | WATERBURY | – | yes | yes |
| 203-726 | Verizon | BRIDGEPORT | 2010-09-08 | yes | yes |
| 203-727 | T-Mobile | BRIDGEPORT | 2001-06-05 | yes | yes |
| 203-728 | AT&T | STAMFORD | 2006-11-22 | yes | yes |
| 203-729 | AT&T | NAUGATUCK | – | – | yes |
| 203-730 | AT&T | DANBURY | – | – | yes |
| 203-731 | AT&T | DANBURY | – | yes | yes |
| 203-732 | AT&T | ANSONIDRBY | – | – | yes |
| 203-733 | Verizon | DANBURY | – | – | yes |
| 203-734 | AT&T | ANSONIDRBY | – | – | yes |
| 203-735 | AT&T | ANSONIDRBY | – | – | yes |
| 203-736 | AT&T | ANSONIDRBY | – | yes | yes |
| 203-737 | AT&T | NEW HAVEN | – | yes | yes |
| 203-738 | Windstream | GUILFORD | – | yes | yes |
| 203-739 | AT&T | DANBURY | – | yes | yes |
| 203-740 | AT&T | DANBURY | – | – | yes |
| 203-741 | AT&T | WALLINGFD | – | yes | yes |
| 203-742 | Verizon | GREENWICH | 2003-04-10 | yes | yes |
| 203-743 | AT&T | DANBURY | – | – | yes |
| 203-744 | AT&T | DANBURY | – | yes | yes |
| 203-745 | AT&T | NEW HAVEN | – | yes | yes |
| 203-746 | AT&T | DANBURY | – | – | yes |
| 203-747 | AT&T | NEW HAVEN | – | yes | yes |
| 203-748 | AT&T | DANBURY | – | – | yes |
| 203-749 | AT&T | DANBURY | – | – | yes |
| 203-750 | AT&T | NORWALK | – | – | yes |
| 203-751 | AT&T | ANSONIDRBY | – | yes | yes |
| 203-752 | AT&T | NEW HAVEN | – | yes | yes |
| 203-753 | AT&T | WATERBURY | – | – | yes |
| 203-754 | AT&T | WATERBURY | – | – | yes |
| 203-755 | AT&T | WATERBURY | – | – | yes |
| 203-756 | AT&T | WATERBURY | – | – | yes |
| 203-757 | AT&T | WATERBURY | – | – | yes |
| 203-758 | AT&T | WATERBURY | – | – | yes |
| 203-759 | AT&T | WATERBURY | – | yes | yes |
| 203-760 | Peerless | BRIDGEPORT | 2012-04-16 | yes | yes |
| 203-761 | AT&T | WILTON | – | – | yes |
| 203-762 | AT&T | WILTON | – | yes | yes |
| 203-763 | Lumen | FAIRFIELD | – | yes | yes |
| 203-764 | AT&T | NEW HAVEN | – | yes | yes |
| 203-765 | AT&T | NEW HAVEN | – | – | yes |
| 203-766 | American Messaging | NEW HAVEN | – | – | yes |
| 203-767 | Verizon | BRIDGEPORT | – | – | yes |
| 203-768 | T-Mobile | WATERBURY | – | – | yes |
| 203-769 | Verizon | GREENWICH | – | yes | yes |
| 203-770 | AT&T | DANBURY | – | – | yes |
| 203-771 | AT&T | NEW HAVEN | – | – | yes |
| 203-772 | AT&T | NEW HAVEN | – | yes | yes |
| 203-773 | AT&T | NEW HAVEN | – | – | yes |
| 203-774 | Windstream | WALLINGFD | – | yes | yes |
| 203-775 | AT&T | DANBURY | – | – | yes |
| 203-776 | AT&T | NEW HAVEN | – | – | yes |
| 203-777 | AT&T | NEW HAVEN | – | – | yes |
| 203-778 | AT&T | DANBURY | – | – | yes |
| 203-779 | Windstream | MADISON | – | yes | yes |
| 203-780 | Peerless | NEW HAVEN | 2012-10-02 | yes | yes |
| 203-781 | AT&T | NEW HAVEN | – | yes | yes |
| 203-782 | AT&T | NEW HAVEN | – | – | yes |
| 203-783 | AT&T | MILFORD | – | – | yes |
| 203-784 | AT&T | NEW HAVEN | – | – | yes |
| 203-785 | AT&T | NEW HAVEN | – | – | yes |
| 203-786 | AT&T | NEW HAVEN | – | – | yes |
| 203-787 | AT&T | NEW HAVEN | – | yes | yes |
| 203-788 | AT&T | DANBURY | – | – | yes |
| 203-789 | AT&T | NEW HAVEN | – | – | yes |
| 203-790 | AT&T | DANBURY | – | – | yes |
| 203-791 | AT&T | DANBURY | – | – | yes |
| 203-792 | AT&T | DANBURY | – | – | yes |
| 203-793 | Lumen | WALLINGFD | 2001-03-23 | yes | yes |
| 203-794 | AT&T | DANBURY | – | yes | yes |
| 203-795 | AT&T | NEW HAVEN | – | – | yes |
| 203-796 | AT&T | DANBURY | – | – | yes |
| 203-797 | AT&T | DANBURY | – | – | yes |
| 203-798 | AT&T | DANBURY | – | – | yes |
| 203-799 | AT&T | NEW HAVEN | – | – | yes |
| 203-800 | T-Mobile | NEW HAVEN | 2011-03-10 | yes | yes |
| 203-801 | AT&T | NEW CANAAN | – | yes | yes |
| 203-802 | T-Mobile | WATERBURY | 2008-10-03 | yes | yes |
| 203-803 | Verizon | NORWALK | – | yes | yes |
| 203-804 | AT&T | NEW HAVEN | – | – | yes |
| 203-805 | AT&T | WATERBURY | – | yes | yes |
| 203-806 | AT&T | CHESHIRE | – | yes | yes |
| 203-807 | AT&T | NORWALK | 2001-01-30 | yes | yes |
| 203-808 | T-Mobile | WATERBURY | 2002-05-30 | yes | yes |
| 203-809 | T-Mobile | NEW HAVEN | 2002-11-04 | yes | yes |
| 203-810 | Altice | NORWALK | 2001-07-27 | yes | yes |
| 203-812 | AT&T | NEW HAVEN | – | yes | yes |
| 203-813 | AT&T | BYRAM | – | yes | yes |
| 203-814 | Verizon | BRIDGEPORT | – | yes | yes |
| 203-815 | Verizon | NEW HAVEN | – | yes | yes |
| 203-816 | Lumen | TRUMBULL | 2001-03-14 | yes | yes |
| 203-817 | Altice | STAMFORD | – | yes | yes |
| 203-818 | Verizon | NORWALK | – | yes | yes |
| 203-819 | AT&T | WATERBURY | – | yes | yes |
| 203-820 | T-Mobile | NORWALK | – | yes | yes |
| 203-821 | AT&T | NEW HAVEN | – | yes | yes |
| 203-822 | AT&T | NORWALK | – | yes | yes |
| 203-823 | Comcast | NEW HAVEN | – | yes | yes |
| 203-824 | AT&T | NEW HAVEN | – | – | yes |
| 203-825 | AT&T | DANBURY | – | – | yes |
| 203-826 | AT&T | DANBURY | – | yes | yes |
| 203-827 | Verizon | OLDGRNWICH | 2004-07-19 | yes | yes |
| 203-828 | Lumen | SEYMOUR | – | yes | yes |
| 203-829 | T-Mobile | NORWALK | – | yes | yes |
| 203-830 | AT&T | DANBURY | – | yes | yes |
| 203-831 | AT&T | NORWALK | – | – | yes |
| 203-832 | AT&T | STAMFORD | 2006-04-06 | yes | yes |
| 203-833 | Verizon | NEW HAVEN | 2015-07-29 | yes | yes |
| 203-834 | AT&T | WILTON | – | – | yes |
| 203-835 | Spok | NORWALK | – | – | yes |
| 203-836 | Verizon | NEW HAVEN | 2011-12-06 | yes | yes |
| 203-837 | AT&T | DANBURY | – | yes | yes |
| 203-838 | AT&T | NORWALK | – | – | yes |
| 203-839 | Spok | NORWALK | – | – | yes |
| 203-840 | AT&T | NORWALK | – | – | yes |
| 203-841 | Windstream | WATERBURY | – | yes | yes |
| 203-842 | Lumen | NORWALK | – | yes | yes |
| 203-843 | AT&T | NEW HAVEN | – | yes | yes |
| 203-844 | Verizon | FAIRFIELD | 2004-08-16 | yes | yes |
| 203-845 | AT&T | NORWALK | – | – | yes |
| 203-846 | AT&T | NORWALK | – | – | yes |
| 203-847 | AT&T | NORWALK | – | – | yes |
| 203-848 | Windstream | NEW HAVEN | – | yes | yes |
| 203-849 | AT&T | NORWALK | – | – | yes |
| 203-850 | T-Mobile | NEW HAVEN | 2008-10-03 | yes | yes |
| 203-851 | AT&T | NORWALK | – | yes | yes |
| 203-852 | AT&T | NORWALK | – | – | yes |
| 203-853 | AT&T | NORWALK | – | – | yes |
| 203-854 | AT&T | NORWALK | – | – | yes |
| 203-855 | AT&T | NORWALK | – | – | yes |
| 203-856 | Verizon | NORWALK | – | – | yes |
| 203-857 | AT&T | NORWALK | – | yes | yes |
| 203-858 | Verizon | NORWALK | – | – | yes |
| 203-859 | Verizon | NEW HAVEN | – | yes | yes |
| 203-861 | Verizon | GREENWICH | – | – | yes |
| 203-862 | Verizon | GREENWICH | – | – | yes |
| 203-863 | Verizon | GREENWICH | – | – | yes |
| 203-864 | T-Mobile | BRIDGEPORT | 2011-03-07 | yes | yes |
| 203-865 | AT&T | NEW HAVEN | – | – | yes |
| 203-866 | AT&T | NORWALK | – | – | yes |
| 203-867 | AT&T | NEW HAVEN | – | – | yes |
| 203-868 | AT&T | NEW HAVEN | – | yes | yes |
| 203-869 | Verizon | GREENWICH | – | – | yes |
| 203-870 | Altice | BRIDGEPORT | – | yes | yes |
| 203-871 | AT&T | BRANFORD | – | yes | yes |
| 203-872 | Bandwidth | CHESHIRE | – | yes | yes |
| 203-873 | AT&T | BRIDGEPORT | 2007-02-07 | yes | yes |
| 203-874 | AT&T | MILFORD | – | – | yes |
| 203-875 | AT&T | DARIEN | – | yes | yes |
| 203-876 | AT&T | MILFORD | – | – | yes |
| 203-877 | AT&T | MILFORD | – | – | yes |
| 203-878 | AT&T | MILFORD | – | – | yes |
| 203-879 | AT&T | WOLCOTT | – | – | yes |
| 203-880 | AT&T | TRUMBULL | – | yes | yes |
| 203-881 | AT&T | SEYMOUR | – | yes | yes |
| 203-882 | AT&T | MILFORD | – | – | yes |
| 203-883 | Lumen | STAMFORD | – | yes | yes |
| 203-884 | Onvoy | GUILFORD | – | yes | yes |
| 203-885 | Verizon | DANBURY | 2006-10-30 | yes | yes |
| 203-886 | Windstream | MERIDEN | – | yes | yes |
| 203-887 | T-Mobile | NEW HAVEN | – | yes | yes |
| 203-888 | AT&T | SEYMOUR | – | – | yes |
| 203-889 | Lumen | NEW HAVEN | – | yes | yes |
| 203-890 | AT&T | STAMFORD | 2001-07-27 | yes | yes |
| 203-891 | AT&T | NEW HAVEN | – | yes | yes |
| 203-892 | T-Mobile | ANSONIDRBY | 2010-11-08 | yes | yes |
| 203-893 | Verizon | ANSONIDRBY | 2007-06-29 | yes | yes |
| 203-894 | AT&T | RIDGEFIELD | – | yes | yes |
| 203-895 | AT&T | TRUMBULL | – | – | yes |
| 203-896 | Peerless | MADISON | – | yes | yes |
| 203-897 | Verizon | STAMFORD | 2008-08-20 | yes | yes |
| 203-898 | Verizon | DARIEN | 2005-01-31 | yes | yes |
| 203-899 | AT&T | NORWALK | – | – | yes |
| 203-900 | CSC VOICE, LLC | GREENWICH | 2012-02-24 | yes | yes |
| 203-901 | T-Mobile | NEW HAVEN | – | yes | yes |
| 203-902 | Onvoy | NEW HAVEN | – | – | yes |
| 203-903 | Lumen | NEW HAVEN | – | yes | yes |
| 203-904 | T-Mobile | NORWALK | – | yes | yes |
| 203-905 | AT&T | STAMFORD | – | yes | yes |
| 203-906 | Verizon | ANSONIDRBY | 2002-04-23 | yes | yes |
| 203-907 | Windstream | NEW HAVEN | – | yes | yes |
| 203-908 | T-Mobile | BRIDGEPORT | 2006-04-05 | yes | yes |
| 203-909 | Verizon | NEW HAVEN | 2008-05-13 | yes | yes |
| 203-910 | Verizon | WATERBURY | – | – | yes |
| 203-912 | Verizon | STAMFORD | – | – | yes |
| 203-913 | Verizon | BRIDGEPORT | – | – | yes |
| 203-914 | CSC VOICE, LLC | STAMFORD | 2012-02-24 | yes | yes |
| 203-915 | Verizon | NEW HAVEN | – | – | yes |
| 203-916 | Lumen | BRIDGEPORT | 2001-01-30 | yes | yes |
| 203-917 | Verizon | DANBURY | 2008-10-22 | yes | yes |
| 203-918 | AT&T | STAMFORD | – | – | yes |
| 203-919 | T-Mobile | NORWALK | – | yes | yes |
| 203-920 | Verizon | NEW CANAAN | 2004-02-20 | yes | yes |
| 203-921 | AT&T | STAMFORD | – | yes | yes |
| 203-922 | AT&T | HUNTINGTON | – | yes | yes |
| 203-923 | Verizon | BRIDGEPORT | – | yes | yes |
| 203-924 | AT&T | HUNTINGTON | – | – | yes |
| 203-925 | AT&T | HUNTINGTON | – | – | yes |
| 203-926 | AT&T | HUNTINGTON | – | – | yes |
| 203-927 | Verizon | NEW HAVEN | – | yes | yes |
| 203-928 | AT&T | NEW HAVEN | – | yes | yes |
| 203-929 | AT&T | HUNTINGTON | – | – | yes |
| 203-930 | Lumen | GREENWICH | 2001-03-14 | yes | yes |
| 203-931 | AT&T | NEW HAVEN | – | yes | yes |
| 203-932 | AT&T | NEW HAVEN | – | – | yes |
| 203-933 | AT&T | NEW HAVEN | – | – | yes |
| 203-934 | AT&T | NEW HAVEN | – | – | yes |
| 203-935 | Lumen | MERIDEN | – | yes | yes |
| 203-936 | AT&T | NEW HAVEN | 2008-09-12 | yes | yes |
| 203-937 | AT&T | NEW HAVEN | – | yes | yes |
| 203-938 | AT&T | REDDING | – | – | yes |
| 203-939 | CSC VOICE, LLC | NORWALK | 2008-06-25 | yes | yes |
| 203-940 | AT&T | STAMFORD | – | yes | yes |
| 203-941 | Bandwidth | SEYMOUR | 2010-09-21 | yes | yes |
| 203-942 | T-Mobile | DANBURY | – | yes | yes |
| 203-943 | T-Mobile | NORWALK | – | yes | yes |
| 203-944 | AT&T | HUNTINGTON | – | – | yes |
| 203-945 | AT&T | NORWALK | – | yes | yes |
| 203-946 | AT&T | NEW HAVEN | – | – | yes |
| 203-947 | AT&T | DANBURY | – | yes | yes |
| 203-948 | T-Mobile | DANBURY | – | yes | yes |
| 203-949 | AT&T | WALLINGFD | – | – | yes |
| 203-951 | AT&T | MILFORD | – | yes | yes |
| 203-952 | T-Mobile | NORWALK | – | yes | yes |
| 203-953 | T-Mobile | BRIDGEPORT | 2001-07-27 | yes | yes |
| 203-954 | Windstream | ANSONIDRBY | – | yes | yes |
| 203-955 | Verizon | FAIRFIELD | 2004-02-20 | yes | yes |
| 203-956 | Altice | NORWALK | 2001-01-30 | yes | yes |
| 203-957 | CSC VOICE, LLC | NORWALK | 2011-05-25 | yes | yes |
| 203-960 | Altice | STAMFORD | 2008-09-15 | yes | yes |
| 203-961 | AT&T | STAMFORD | – | yes | yes |
| 203-962 | AT&T | STAMFORD | – | yes | yes |
| 203-963 | AT&T | NORWALK | – | yes | yes |
| 203-964 | AT&T | STAMFORD | – | yes | yes |
| 203-965 | AT&T | STAMFORD | – | yes | yes |
| 203-966 | AT&T | NEW CANAAN | – | – | yes |
| 203-967 | AT&T | STAMFORD | – | – | yes |
| 203-968 | AT&T | STAMFORD | – | yes | yes |
| 203-969 | AT&T | STAMFORD | – | yes | yes |
| 203-970 | Altice | NORWALK | 2011-04-04 | yes | yes |
| 203-971 | Altice | GREENWICH | – | yes | yes |
| 203-972 | AT&T | NEW CANAAN | – | – | yes |
| 203-973 | AT&T | STAMFORD | – | yes | yes |
| 203-974 | AT&T | NEW HAVEN | – | yes | yes |
| 203-975 | AT&T | STAMFORD | – | – | yes |
| 203-977 | AT&T | STAMFORD | – | – | yes |
| 203-978 | AT&T | STAMFORD | – | yes | yes |
| 203-979 | AT&T | STAMFORD | – | – | yes |
| 203-980 | Verizon | NEW HAVEN | 2002-08-20 | yes | yes |
| 203-981 | T-Mobile | NORWALK | – | yes | yes |
| 203-982 | T-Mobile | WATERBURY | – | yes | yes |
| 203-983 | Windstream | GREENWICH | – | yes | yes |
| 203-984 | Verizon | NORWALK | – | – | yes |
| 203-985 | AT&T | NEW HAVEN | – | yes | yes |
| 203-986 | Verizon | OLDGRNWICH | 2004-02-20 | yes | yes |
| 203-987 | Lumen | GREENWICH | 2001-03-30 | yes | yes |
| 203-988 | AT&T | NEW HAVEN | – | – | yes |
| 203-989 | Lumen | STAMFORD | – | yes | yes |
| 203-990 | Verizon | OLDGRNWICH | 2005-01-31 | yes | yes |
| 203-991 | AT&T | NORWALK | – | – | yes |
| 203-992 | CSC VOICE, LLC | GREENWICH | 2006-05-12 | yes | yes |
| 203-993 | Verizon | BRIDGEPORT | 2006-07-20 | yes | yes |
| 203-994 | T-Mobile | DANBURY | 2001-12-14 | yes | yes |
| 203-995 | Verizon | BRIDGEPORT | 2008-10-08 | yes | yes |
| 203-996 | T-Mobile | NEW HAVEN | 2001-12-14 | yes | yes |
| 203-997 | T-Mobile | ANSONIDRBY | 2011-05-18 | yes | yes |
| 203-998 | Lumen | STAMFORD | 2004-10-15 | yes | yes |
| 203-999 | T-Mobile | NEW HAVEN | 2011-03-09 | yes | yes |
Frequently asked
How many prefixes does area code 203 have?
784 NXX blocks are assigned of 786 possible. Each block is 10,000 consecutive numbers, so the code currently covers about 7,840 thousand-number ranges across 33 rate centers.
What do the first three digits after 203 tell me?
They identify the block, which tells you the rate center it was allocated to and the carrier that received it. They do not tell you who serves the number today: portability moves numbers between carriers, and pooling splits a block between several of them.
Is a 203 prefix tied to a specific town?
To a rate center, which is billing geography rather than a town. NANPA abbreviates rate center names to ten characters and in large metros uses zone codes, so the name is a NANPA label, not a place name.
What does “pooled” mean in the 203 table?
That the block is in thousands-block pooling: carriers draw 1,000-number lots from it instead of taking all 10,000. 473 of 203's blocks are pooled, which is how regulators slowed down area code exhaustion – and why one prefix can belong to several carriers.
Source and limits
NANPA CO Code Assignment Records, all states, utilized codes, file updated 11/01/2026 – the rows where the record's Use field is “AS” (assigned). Unavailable codes are excluded. The records say who received a block and when, not who serves a particular number today.
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