203
Area code 203
Connecticut, United States
National (203) 555-0123, E.164 +12035550123
How the 800 central office codes (exchanges) of area code 203 were allocated, from the North American Numbering Plan's records: to which carrier, as which line type. A 203 number is mobile, fixed line or VoIP according to its exchange, the three digits after the area code; the allocation is the original one (below).
At a glance
- Country code
- +1
- State
- CT
- Exchanges on record
- 800
- Carriers on record
- 15
- Mobile 200 (25%)
- Fixed line 560 (70%)
- VoIP 24 (3%)
- No line type on record 16 (2%)
- 800 exchanges on record
Most exchanges: Frontier 338, Verizon 117, AT&T 99.
Check a number
Valid fixed line or mobile number in the United States.
+1
country code
203
area code
5550123
subscriber number
| Country | United States numbering plan |
|---|---|
| Line type | Fixed line or mobile |
| Carrier the block was allocated to | No carrier on record for this prefix |
| E.164 | +12035550123 |
| International | +1 203-555-0123 |
| National | (203) 555-0123 |
| RFC 3966 | tel:+1-203-555-0123 |
Source: North American Numbering Plan Administrator (NANPA); Canadian Numbering Administrator (CNAC); National numbering plan: United States (ITU)
The example is 203-555-0123: 555-0100 to 555-0199 are set aside for fictional use in every area code.
The exchange map
One cell per exchange: blocks 203 2xx to 203 9xx; in each block the row is the tens digit, the column the units digit.
- Mobile 200
- Fixed line 560
- VoIP 24
- No line type on record 16
Formats and patterns
| E.164 | +12035550123 |
|---|---|
| International | +1 203-555-0123 |
| National | (203) 555-0123 |
| RFC 3966 (tel: URI) | tel:+1-203-555-0123 |
Any 203 number, in E.164
^\+1203[2-9]\d{6}$+1, the area code, a central office code that does not start with 0 or 1, then four digits.
Mobile exchanges (200 on record)
^\+1203(?:2(?:0[169]|1[2-9]|2[38]|3[1-3]|4[013679]|5[378]|[69]0|7[3489]|8[29])|3(?:0[0589]|1[34]|4[23]|60|7[06]|9[58])|4(?:00|1[02457]|24|3[045]|4[49]|5[016]|6[04]|7[07]|82|9[46])|5(?:0[015-79]|1[02589]|2[0-24-6]|3[067]|4[035]|5[0468]|6[015]|7[02]|8[49]|9[23])|6(?:0[056]|[12][37]|31|4[0145]|5[07]|6[78]|7[0156]|8[45]|90)|7(?:07|1[045]|2[1267]|33|6[6-8]|70|88)|8(?:0[02-47-9]|1[459]|2[049]|3[23569]|[47]3|5[068]|64|8[57]|9[235])|9(?:0[14689]|1[02357-9]|27|4[2378]|5[23]|79|8[0-248]|9[34679]))\d{4}$Fixed line exchanges (560 on record)
^\+1203(?:2(?:0[2457]|10|2[0-24-79]|3[04-9]|4[2458]|5[0-24-69]|[69][1-9]|7[0-25-7]|8[013-8])|3(?:0[1-467]|1[025-9]|[2358]\d|4[014-9]|6[1-9]|7[1-57-9]|9[0-4679])|4(?:0[1-79]|1[3689]|2[0-35-9]|3[16-8]|4[1-35-8]|5[2-57-9]|6[1-35-9]|7[1-4689]|8[013-9]|9[02357-9])|5(?:0[2-48]|1[3467]|2[37-9]|3[1-489]|4[124689]|5[1-379]|6[2-46-9]|7[13-9]|8[1-35-8]|9[014-9])|6(?:0[1-47-9]|1[024-689]|2[0-24-689]|3[02-9]|4[237-9]|5[1-689]|6[1-69]|7[2-47-9]|8[0-36-9]|9[1-9])|7(?:0[1-689]|1[26-9]|2[03489]|3[0-24-9]|[459]\d|6[1-59]|7[1-9]|8[1-79])|8(?:0[156]|1[0236-8]|2[125-8]|3[01478]|4[0-24-9]|5[1-579]|6[1-35-9]|7[014-9]|8[0-3689]|9[0147-9])|9(?:0[0357]|1[46]|2[0-689]|[36]\d|4[04-69]|5[14-7]|7[0-578]|8[35-79]|9[0-258]))\d{4}$VoIP exchanges (24 on record)
^\+1203(?:20[038]|4(?:08|3[239]|40|91)|5(?:35|47|80)|6(?:46|60)|7(?:13|25|[68]0)|8(?:23|72|84|96)|9(?:02|41))\d{4}$The exchange patterns follow the original allocations; a number ported since keeps its digits but not necessarily its carrier or its line type.
Carriers and their exchanges
Every carrier holding exchanges in 203, with the exchanges allocated to it (the three digits after the area code).
| Carrier | Exchanges | Mobile | Fixed line | VoIP | Exchanges held |
|---|---|---|---|---|---|
| Frontier | 338 | 0 | 338 | 0 | 205, 207, 221–222, 224–227, 229–230, 234–239, 245, 248, 250–251, 254–256, 259, 261–272, 275, 281, 284, 287–288, 291, 294, 299, 301, 312, 315–319, 321–339, 341, 346, 348, 351–353, 356–359, 362–368, 371–375, 377–387, 389, 392–394, 396–397, 401–402, 406–407, 416, 419–421, 425–426, 431, 436, 438, 445, 452–454, 457–459, 461–462, 465–469, 471–474, 476, 478–479, 481, 483–484, 486, 488, 492, 495, 497–499, 502–503, 527, 534, 539, 541, 544, 553, 562–563, 573–579, 581–582, 585, 591, 595–598, 602–603, 609, 614–615, 619, 624, 630, 634, 637, 639, 654–656, 662, 674, 677, 679–680, 686, 688, 691, 694–699, 703, 708–709, 720, 723, 728–732, 734–737, 739–741, 743–746, 748–759, 761–762, 764–765, 771–773, 775–778, 781–787, 789–792, 794–799, 801, 812, 821, 825–826, 830–831, 834, 837–838, 840, 845–847, 849, 851–855, 857, 865–867, 874, 876–879, 881–882, 888, 890–891, 894, 899, 921–922, 924–926, 928–929, 931–934, 936–938, 940, 944–946, 949, 961–969, 972–973, 975, 977–978, 985, 991 |
| Verizon | 117 | 61 | 56 | 0 | 209, 228, 231–233, 240–241, 246–247, 249, 253, 257–258, 273, 277, 280, 293, 295–297, 307–308, 310, 313–314, 320, 369, 376, 388, 391, 399, 422, 427–429, 437, 443, 448, 450, 455–456, 464, 470, 480, 494, 501, 505, 520–521, 530–532, 536, 552, 561, 566, 584, 605, 607, 618, 620, 622–623, 625, 629, 636, 641–642, 644, 661, 671, 681, 705, 707, 719, 721, 726, 733, 742, 767, 769, 803, 814–815, 818, 827, 833, 836, 844, 856, 858–859, 861–863, 869, 885, 893, 897–898, 906, 909–910, 912–913, 915, 917, 920, 923, 927, 955, 980, 984, 986, 990, 993, 995 |
| AT&T | 99 | 52 | 47 | 0 | 204, 206, 212–219, 260, 274, 285, 302–305, 343, 349–350, 390, 400, 403, 409, 414–415, 417–418, 423, 430, 441–442, 444, 446–447, 451, 463, 482, 490, 500, 506, 513–514, 518, 522–525, 529, 540, 542, 546, 551, 554, 556, 558–560, 564, 571, 586, 592, 601, 626, 631, 640, 645, 658, 673, 689, 701, 710, 722, 747, 770, 788, 804–807, 813, 819, 822, 824, 832, 843, 868, 871, 873, 875, 880, 895, 905, 918, 947, 951, 974, 979, 988 |
| T-Mobile | 72 | 72 | 0 | 0 | 223, 243, 278, 290, 300, 309, 360, 395, 410, 424, 434–435, 449, 460, 496, 507, 509–510, 512, 515, 519, 526, 537, 543, 545, 550, 565, 570, 572, 589, 600, 606, 613, 617, 627, 650, 667–668, 670, 675–676, 684–685, 690, 715, 727, 768, 800, 802, 808–809, 820, 829, 850, 864, 887, 892, 901, 904, 908, 919, 942–943, 948, 952–953, 981–982, 994, 996–997, 999 |
| Lumen | 41 | 0 | 41 | 0 | 347, 361, 404, 487, 493, 516–517, 528, 533, 548, 583, 590, 599, 604, 612, 616, 633, 635, 648, 666, 669, 687, 692, 704, 712, 716, 718, 763, 793, 816, 828, 842, 883, 889, 903, 916, 930, 935, 987, 989, 998 |
| Paetec Itel | 40 | 0 | 40 | 0 | 286, 306, 405, 413, 504, 508, 538, 549, 567–568, 608, 610, 621, 632, 638, 643, 647, 649, 651–653, 659, 663, 665, 672, 678, 682–683, 702, 706, 724, 738, 774, 779, 841, 848, 886, 907, 954, 983 |
| Cablevision Lightpath | 29 | 0 | 29 | 0 | 202, 210, 220, 242, 252, 276, 283, 292, 298, 340, 344–345, 354–355, 485, 489, 557, 569, 588, 594, 628, 693, 810, 817, 870, 956, 960, 970–971 |
| USA Mobility | 10 | 10 | 0 | 0 | 201, 279, 282, 289, 342, 398, 477, 593, 835, 839 |
| Optimum | 9 | 0 | 9 | 0 | 244, 587, 664, 717, 900, 914, 939, 957, 992 |
| Comcast | 7 | 0 | 0 | 7 | 208, 433, 439–440, 535, 725, 823 |
| Onvoy | 7 | 0 | 0 | 7 | 203, 547, 646, 660, 713, 884, 902 |
| Bandwidth.com | 6 | 0 | 0 | 6 | 200, 408, 432, 491, 872, 941 |
| American Messaging | 4 | 4 | 0 | 0 | 370, 412, 657, 766 |
| Peerless Network | 4 | 0 | 0 | 4 | 580, 760, 780, 896 |
| Emergency Networks | 1 | 1 | 0 | 0 | 714 |
Questions developers ask
- Where is area code 203?
- Area code 203 is in Connecticut, in the United States: all 800 of its exchanges on record are there. From abroad it is dialled +1 203, then the seven-digit number.
- Is a 203 number mobile or landline?
- Either: in the North American Numbering Plan the line type belongs to the exchange (the three digits after the area code), not to the area code. Of the 800 exchanges on record in 203, 200 (25%) were allocated as mobile, 560 (70%) as fixed line, 24 (3%) as VoIP and 16 (2%) have no line type on record. A number can have been ported since, to another carrier and even to another line type.
- Which carriers have numbers in area code 203?
- 15 carriers hold exchanges in 203 on record; the most: Frontier (338), Verizon (117) and AT&T (99). These are the original allocations: with number portability, a number may be served by another carrier today, which only a live carrier lookup (an HLR or MNP query) can tell.
- How do I validate a 203 phone number?
- In E.164 a 203 number matches ^\+1203[2-9]\d{6}$: +1, the area code, a central office code that does not start with 0 or 1, then four digits. Written nationally it reads (203) 555-0123. The exchange patterns on this page narrow it to the exchanges allocated as mobile, fixed line or VoIP.