{ "url": "https://phonelookup.dev/prefix/us-203", "npa": "203", "slug": "us-203", "iso": "US", "country": "United States", "regions": [ { "code": "CT", "name": "Connecticut", "exchanges": 800 } ], "exchanges": 800, "known": 784, "byLineType": { "fixed_line": 560, "mobile": 200, "unknown": 16, "voip": 24 }, "carriers": [ { "name": "Frontier", "exchanges": 338, "byLineType": { "fixed_line": 338 }, "ranges": [ "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" ] }, { "name": "Verizon", "exchanges": 117, "byLineType": { "fixed_line": 56, "mobile": 61 }, "ranges": [ "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" ] }, { "name": "AT&T", "exchanges": 99, "byLineType": { "fixed_line": 47, "mobile": 52 }, "ranges": [ "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" ] }, { "name": "T-Mobile", "exchanges": 72, "byLineType": { "mobile": 72 }, "ranges": [ "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" ] }, { "name": "Lumen", "exchanges": 41, "byLineType": { "fixed_line": 41 }, "ranges": [ "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" ] }, { "name": "Paetec Itel", "exchanges": 40, "byLineType": { "fixed_line": 40 }, "ranges": [ "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" ] }, { "name": "Cablevision Lightpath", "exchanges": 29, "byLineType": { "fixed_line": 29 }, "ranges": [ "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" ] }, { "name": "USA Mobility", "exchanges": 10, "byLineType": { "mobile": 10 }, "ranges": [ "201", "279", "282", "289", "342", "398", "477", "593", "835", "839" ] }, { "name": "Optimum", "exchanges": 9, "byLineType": { "fixed_line": 9 }, "ranges": [ "244", "587", "664", "717", "900", "914", "939", "957", "992" ] }, { "name": "Comcast", "exchanges": 7, "byLineType": { "voip": 7 }, "ranges": [ "208", "433", "439–440", "535", "725", "823" ] }, { "name": "Onvoy", "exchanges": 7, "byLineType": { "voip": 7 }, "ranges": [ "203", "547", "646", "660", "713", "884", "902" ] }, { "name": "Bandwidth.com", "exchanges": 6, "byLineType": { "voip": 6 }, "ranges": [ "200", "408", "432", "491", "872", "941" ] }, { "name": "American Messaging", "exchanges": 4, "byLineType": { "mobile": 4 }, "ranges": [ "370", "412", "657", "766" ] }, { "name": "Peerless Network", "exchanges": 4, "byLineType": { "voip": 4 }, "ranges": [ "580", "760", "780", "896" ] }, { "name": "Emergency Networks", "exchanges": 1, "byLineType": { "mobile": 1 }, "ranges": [ "714" ] } ], "grid": "vmfvffmfvmfummmmmmmmfffmffffmffmmmffffffmmfmffmmfmfffmfffmmfmffffffffffffmmfffmmffmffffffmmfffffffffmffffmffmmfufmmfffffffffffffffffffffffffffmmffffffffffffffffmfffffffffmfffffmffffffffffffffffffmffmfmfffffffvfmumfmmfmffffffmfffffmfvvmmfffvvfffmffffmmmffffmfffmfffmfffffmffffufmffffmffffffffvffmfmfffmmfffmmmfmmumffmffmmmmmfmmmfffmffffvmmffmffmfmfvffmfffmumfmfmmfffmffffmfmfffffffvfffmffffmffmmffffffmffffmmffffufmfffmfffffmfffmfffmffffffffmmffmmvfffmffffffmffvffffffmmfmmfffmmfffffffmmffffmfffffffffuffffffmffmufvmmfffffmmffvmmfffffmffffffffffffffffffffffffffvfffffmmmfmfffffffffvfffffffmfffffffffffmfmmmffmmmfuffmmfffmmffvmffffmffmmfmmffmfffmffffffmfffffmfmfufffmfffffffvmffffffffffvmfmffffmmfmvffffmvfmfmfmmmummfmfmmmfffffffmfffffffffffffvmmfffmmfufmmffffuuffffffffffffffffuffmmmmfmfffmffffmmfmmfm", "patterns": { "all": "^\\+1203[2-9]\\d{6}$", "fixed_line": "^\\+1203(?:2(?:0[2457]|10|2[0-24-79]|3[04-9]|4[2458]|5[0-24-69]|[69][1-9]|7[0-25-7]|8[013-8])|3(?:0[1-467]|1[025-9]|[2358]\\d|4[014-9]|6[1-9]|7[1-57-9]|9[0-4679])|4(?:0[1-79]|1[3689]|2[0-35-9]|3[16-8]|4[1-35-8]|5[2-57-9]|6[1-35-9]|7[1-4689]|8[013-9]|9[02357-9])|5(?:0[2-48]|1[3467]|2[37-9]|3[1-489]|4[124689]|5[1-379]|6[2-46-9]|7[13-9]|8[1-35-8]|9[014-9])|6(?:0[1-47-9]|1[024-689]|2[0-24-689]|3[02-9]|4[237-9]|5[1-689]|6[1-69]|7[2-47-9]|8[0-36-9]|9[1-9])|7(?:0[1-689]|1[26-9]|2[03489]|3[0-24-9]|[459]\\d|6[1-59]|7[1-9]|8[1-79])|8(?:0[156]|1[0236-8]|2[125-8]|3[01478]|4[0-24-9]|5[1-579]|6[1-35-9]|7[014-9]|8[0-3689]|9[0147-9])|9(?:0[0357]|1[46]|2[0-689]|[36]\\d|4[04-69]|5[14-7]|7[0-578]|8[35-79]|9[0-258]))\\d{4}$", "mobile": "^\\+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}$", "voip": "^\\+1203(?:20[038]|4(?:08|3[239]|40|91)|5(?:35|47|80)|6(?:46|60)|7(?:13|25|[68]0)|8(?:23|72|84|96)|9(?:02|41))\\d{4}$" }, "sandbox": { "input": "+12035550123", "valid": true, "type": "Fixed line or mobile", "region": "US", "formats": { "e164": "+12035550123", "international": "+1 203-555-0123", "national": "(203) 555-0123", "rfc3966": "tel:+1-203-555-0123" }, "parts": { "countryCode": "+1", "destinationCode": "203", "destinationKind": "area code", "subscriber": "5550123" } }, "faq": [ { "question": "Where is area code 203?", "answer": "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." }, { "question": "Is a 203 number mobile or landline?", "answer": "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." }, { "question": "Which carriers have numbers in area code 203?", "answer": "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." }, { "question": "How do I validate a 203 phone number?", "answer": "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." } ], "neighbours": { "sameRegion": [ "us-475", "us-860", "us-959" ], "previous": "us-202", "next": "ca-204" }, "meta": { "dataAsOf": "2026-10-25", "dataPoints": 800, "references": [ { "authority": "NANPA", "title": "North American Numbering Plan Administrator", "url": "https://nanpa.com/" }, { "authority": "CNAC", "title": "Canadian Numbering Administrator", "url": "https://www.cnac.ca/" }, { "authority": "ITU", "title": "National numbering plan: United States", "url": "https://www.itu.int/oth/T02020000DE/en" } ] } }