| CoID | Company | Type | Status | States Served | 24X7 Phone |
| CELL1 | Cellular One(Cancelled) | PBX | C | MD, VA | 800-773-7911 |
| CELSO | Telepak Inc d/b/a Cellular South / CSpire Wireless | Wireless/Cellular/PCS | C | AL | MS | TN | 800-772-8250 |
| CELXL | Cellular XL Associates, L.P. (Cancelled - See MEGGT) | Facility | C | MS | 601-402-6876 |
| CENCL | Centennial Wireless (CANCELLED) | Cellular | C | IN, MI, OH, LA, MS, TX | 219-750-3802 |
| CENGA | Central Georgia Technology LLC | 9-1-1 Admin-CPE ALI (9-1-1 Jurisdiction/PSAP ONLY) VoIP Reseller | A | USA - Nationwide | 470-481-0400 |
| CENPR | Centennial de Puerto Rico - CANCELLED | CLEC Facility | CLEC Reseller | CLEC UNE | Internet Protocol Relay Provider | | C | PR | 787-717-9920 |
| CENSU | Census Bureau - CANCELLED | VoIP | C | MD | 301-763-2196 |
| CENTA | Antares Technology Solutions Holdco Inc dba Centaris | VoIP Reseller | A | USA - Nationwide | 231-838-9951 |
| CENTC | CentraCom Interactive | ILEC | A | UT | 435-427-3331 |
| CEPBT | EPB Fiber Optics | CLEC Facility VoIP Provider | A | GA | TN | 423-648-4662 |
| CERR | City of Cerritos | PBX/PS911/Shared Tenant | A | CA | 562-860-0044 |
| CES09 | Conway Elementary School - CANCELLED | PBX/PS911/Shared Tenant | C | NH | 603-447-8368 |
| CESU | Chittenden East Supervisory Union - CANCELLED | PBX/PS911/Shared Tenant | C | VT | 802-730-2772 |
| CET | Consolidated Communications of NY Company f/k/a Chautauqua & | ILEC | A | NY | 916-746-3000 |
| CETUT | Carbon Emery Telcom | ILEC | A | UT | 435-748-2223 |
| CFB | CFBTEL | VoIP Reseller VoIP Provider | A | USA - Nation Wide | 844-505-0349 |
| CFLY | Greenfly Networks Inc dba Clearfly | VoIP Reseller | A | USA - Nation Wide | 866-652-7520 |
| CFS | Community Fiber Solutions Inc. | Wireless/Cellular/PCS | A | IL | IN | OH | 866-246-9580 |
| CFWAN | CFW Cellular (Cancelled) | Analog Cel | C | Rockingham, Augusta, Highland Counties in VA | 888-377-2845 |
| CFWC | NTELOS (Cancelled) | Facility | C | VA, WV, KY, NC, OH, PA | 540-941-4800 |
| CFWDI | Sprint (formerly NTELOS) - CANCELLED | Wireless/Cellular/PCS | C | KY | MD | NC | OH | PA | VA | WV | 800-877-7330 |
| CGBL | Conduit Global - CANCELLED | PBX/PS911/Shared Tenant | C | USA - Nationwide | 866-594-4636 |
| CGCG9 | Cyber Guardian Consulting Group LLC. | VoIP Reseller | A | NY | 845-444-8273 |
| CGIC | Concord Group Insurance Companies | Facility | A | NH | 877-340-2555 |
| CGMLU | Carnegie Mellon University | 9-1-1 Admin-CPE ALI (9-1-1 Jurisdiction/PSAP ONLY) | A | PA | 412-268-2323 |
| CGPWI | Central Garden & Pet - CANCELLED | PBX/PS911/Shared Tenant | C | WI | 847-707-0083 |
| CGRNH | Grafton County | PBX/PS911/Shared Tenant | A | NH | 603-787-2111 |
| CGT | Columbus Grove Telephone - CANCELLED | Facility | C | OH | 419-659-2111 |
| CGTEC | TEC of Jackson Inc | CLEC Facility CLEC Reseller CLEC UNE Wireless/Cellular/PCS VoIP Provider | A | AL | AR | LA | MS | TN | 601-353-9118 |
| CGURU | Content Guru Inc. | PBX/PS911/Shared Tenant | A | USA - Nationwide | 202-449-2857 |
| CHA | The Cambridge Health Alliance (CANCELLED) | PBX | C | MA | 617-665-1000 |
| CHAFY | Chaffey College | PBX/PS911/Shared Tenant | A | CA | 909-652-6327 |
| CHAMP | Champlain College | PBX/PS911/Shared Tenant | A | VT | 802-865-6465 |
| CHAP | Chapman and Cutler LLP | VoIP Provider | A | CA | DC | IL | NY | NC | UT | (312) 827-4989 |
| CHAPS | Midland College | PBX/PS911/Shared Tenant | | TX | 432-685-4734 |
| CHARC | Chariton Valley Communications Corporation | CLEC Facility | A | MO | 800-769-8731 |
| CHARV | Chariton Valley Telephone Corporation | ILEC | A | MO | 800-769-8731 |
| CHASE | Chase Collegiate School | VoIP | A | CT | 203-236-9485 |
| CHB | Boston Children's Hospital | PBX/PS911/Shared Tenant VoIP Provider | A | MA | 617-355-6000 |
| CHC | Chickasaw Holding Company - CANCELLED | ILEC | Facility | C | OK | 800-687-4402 |
| CHC1 | Community Health Center Inc. | an end user/company that needs PSALI services | A | CT | 860-347-6971 |
| CHCM | Chickamauga Telephone Corporation | ILEC | A | GA | 706-375-3361 |
| CHDC | Diageo | PBX/PS911/Shared Tenant | A | TN | 931-408-2400 |
| CHENE | City of Cheney | PBX/PS911/Shared Tenant | A | WA | 509-535-9233 |
| CHERT | Cherokee Telephone Company | ILEC | | OK | 580-916-2624 |
| CHES | Chester Telephone Company | Facility | A | SC | 803-385-2191 |
| CHESA | City of Chesapeake (CANCELLED) | PBX | C | VA | 757-382-6339 |
| CHESH | Town of Cheshire - CANCELLED | PBX/PS911/Shared Tenant | C | CT | 203-271-5500 |
| CHGOV | Charlotte County Goverment | PBX/PS911/Shared Tenant | A | FL | 941-764-5504 |
| CHI | Christian Homes Inc. | VoIP Provider | A | IL | IN | IA | MO | 618-444-8036 |