| CoID | Company | Type | Status | States Served | 24X7 Phone |
| WTTC | Wes-Tex Telephone Cooperative | Co-Op/Rural | ILEC | A | TX | 432-756-3393 |
| WTTEC | West Tennessee Telephone Co. dba TEC Bradford Division | ILEC | A | TN | 731-742-2211 |
| WTXW | Westex Wireless(Cancelled) | Wireless/Cellular/PCS | C | TX | 732-756-3826 |
| WUHS | Western University Of Health Sciences | 9-1-1 Admin-CPE ALI (9-1-1 Jurisdiction/PSAP ONLY) | PBX/PS911/Shared Tenant | A | CA | OR - 2-PRI Main Location Pomona | Californina 1-PR Lebanon | Oregon Campus | 909-469-5432 |
| WUSD | Westside Unified School District - CANCELLED | CLEC Facility | C | CA | 661-722-0716 |
| WVHL | Waverly Hall Telephone LLC | ILEC | A | GA | 706-304-3852 |
| WVI | Wide Voice LLC | CLEC Facililty | A | USA - Nation Wide | 844-844-8444 |
| WVINC | WatsonVoice Inc - CANCELLED | VoIP Provider | C | USA | 334-212-8000 |
| WVRC | Willow Valley Retirement Communities | PBX/PS911/Shared Tenant | A | Lancaster | PA | 717-464-6000 |
| WVRS | Worldview Video Relay Service LLC - CANCELLED | Video Relay Service | C | MN | 866-957-4313 |
| WVTC | Warwick Valley Telephone Company (CANCELLED) | Facility | C | NJ, NY
NY's 24X7 number is 845-986-1111 | 973-764-1111 |
| WVTCC | Alteva of Warwick LLC known as Warwick Valley Telephone Comp | CLEC Facility CLEC Reseller CLEC UNE ILEC | A | NY | NJ | 845-986-1111 |
| WVU | West Virginia University (CANCELLED) | PBX | C | 0 | 304-293-5664 |
| WVW | West Virginia Wireless (CANCELLED) | Wireless | C | WV,Boyd County KY,Lawrence & Gallia County OH | 304-720-5553 |
| WWCSI | 24 / 7 Telcom | CLEC Reseller | A | WI | 715-664-8313 |
| WWPCS | Western Wireless (Cancelled) | Wireless | C | MO, ND, SD, WY, ID, MN, NE, IO, KS, MS, OK, AR, TX, NM, CO, | 206-541-9574 |
| WWRC | Woodrow Wilson Rehabilitation Center (INACTIVE) | PBX/PS911/Shared Tenant | C | VA | 800-345-9972 |
| WWRSD | Westwood Regional School District | PBX/PS911/Shared Tenant | | NJ | 201-259-5763 |
| WWSYS | WW Systems LLC - CANCELLED | Wireless/Cellular/PCS | C | WI | 715-253-2111 |
| WWT | Wahkiakum West Telephone | LEC | A | QWEST/Wahkiakum & Pacific County | WA | 360-465-2211 |
| WWTC | West Wisconsin Telcom Cooperative | ILEC | A | WI | 715-664-8313 |
| WWTEC | WorthwhileTech LLC - CANCELLED | VoIP Reseller | C | USA - Nation Wide | 330-277-2305 |
| WYETH | Wyeth Nutritionals Inc. (Cancelled) | PBX | C | Wyeth Nutritionals | 802-527-0521 |
| WYND | Wyndham Destinations - CANCELLED | 9-1-1 Admin-CPE ALI (9-1-1 Jurisdiction/PSAP ONLY) | C | USA - Nationwide | 214-399-8274 |
| WYNMC | Doubletree Hilton Houston Medical Center | 9-1-1 Admin-CPE ALI (9-1-1 Jurisdiction/PSAP ONLY) | A | USA - Nation Wide | 713-528-7744 |
| WYOM | Wyoming Mutual Telephone Company | Facility | A | Wyoming Iowa Telephone Exchange Jones County | 563-488-2535 |
| WYTX | City of Wylie | PBX/PS911/Shared Tenant | A | TX | 972-442-8171 |
| X2N | X2nSat Inc. | VoIP Reseller VoIP Provider | A | USA - Nationwide | 707-664-5119 |
| X5SOL | Magna5 LLC | CLEC Facility VoIP Provider | A | OR | WA | 844-462-4625 |
| XATEL | XATel, LLC(Inactive) | CLEC Facility | C | ME | 207-283-0129 |
| XBLUE | XBLUE Networks LLC | VoIP Reseller | A | USA - Nationwide | 941-266-4466 |
| XBP | XBP Inc. | PBX/PS911/Shared Tenant VoIP Provider | A | USA - Nation Wide | 9492020310 |
| XCH | Xchange Telecom(Cancelled) | Facility | C | NY, NJ | 877-853-3443 |
| XCY | CMN-RUS Inc. f/k/a Cinergy MetroNet | CLEC Facility | A | IN | 877-407-3224 |
| XENOI | IONEX (Cancelled) | Facility | C | TX, KS, OK, MO | 877-333-2555 |
| XGSG | XG Service Group | VoIP Reseller VoIP Provider | A | USA - Nationwide | 734-245-4100 |
| XIT | XIT Communications | Facility | A | TX | 806-384-3311 |
| XITC | XIT Cellular - CANCELLED | Wireless/Cellular/PCS | C | TX | 806-384-3311 |
| XNW | nWire / TNCI Operating Company - CANCELLED | CLEC Facility CLEC Reseller VoIP Reseller VoIP Provider | C | USA - Nation Wide | 800-511-9048 |
| XOBEE | Xobee Networks Inc. - CANCELLED | VoIP Provider | C | USA - Nationwide | 5594902800 opt. 1 |
| XOP | Opextel LLC - CANCELLED | CLEC Facility | CLEC Reseller | CLE UNE | VoIP Provider | C | FL | 786-693-8331 |
| XOV | Voxline Networks - CANCELLED | VoIP Reseller | C | USA - Nation Wide | 646-556-7314 |
| XOXO | Verizon | PBX/PS911/Shared Tenant | A | USA - Nationwide | 800-483-0911 |
| XPC | Xspedius Corp. (Cancelled - See ACSI) | Facility | C | LA, MS, AL, FL, TN, NC | 877-322-0414 |
| XPT | eXpeTel Communications (CANCELLED) | Facility | C | MS | 800-310-4481 |
| XTEL | Xtel Communications Inc | CLEC Facility | A | USA - Nationwide | 856-596-4000 |
| XTEX | Crosstex Energy Services L.P. | PBX | A | USA | 214-721-9496 |
| YAHOO | YaHoo!, Inc. (Cancelled) | PBX | C | ALL | 800-464-4402 |
| YALE | Yale University | PBX | A | CT | 203-785-4171 |
| YARDI | Yardi Systems Inc | VoIP Provider | A | USA - Nationwide | 805-699-2040 |