| CoID | Company | Type | Status | States Served | 24X7 Phone |
| CORPT | Corporate Tools LLC | VoIP Reseller | A | USA - Nationwide | 307-545-3929 |
| CORR | Corr Wireless Communications L.L.C. - CANCELLED | CMRS | C | AL | 205-625-7600 |
| CORSC | Superior Court of California County of Riverside | VoIP | A | CA | 951-777-3051 |
| CORT | OCM BOCES/Cortland City School District - CANCELLED | 9-1-1 Admin-CPE ALI (9-1-1 Jurisdiction/PSAP ONLY) | C | NY | 800-773-7911 |
| CORTE | Cortel Technologies LLC | VoIP Reseller | A | USA - Nationwide | 2126274200 |
| CORVA | CITY OF ROANOKE VIRGINIA | 9-1-1 Admin-CPE ALI (9-1-1 Jurisdiction/PSAP ONLY) | A | VA | 540-853-2945 |
| COS | City of Staunton (CANCELLED) | PBX/PS911/Shared Tenant | C | Staunton, VA | 540-332-3842 |
| COSA | City of San Angelo - CANCELLED | VoIP Provider | C | TX | 325-656-3579 |
| COSAC | City of Sacramento | 9-1-1 Admin-CPE ALI (9-1-1 Jurisdiction/PSAP ONLY) | A | CA | 916-808-8999 |
| COSC | County of Santa Clara - CANCELLED | PBX/PS911/Shared Tenant | C | CA | 408-299-2515 |
| COSFS | City of Santa Fe Springs | PBX/PS911/Shared Tenant | A | CO | 562-409-7535 |
| COSMA | City of Springfield MA | 9-1-1 Admin-CPE ALI (9-1-1 Jurisdiction/PSAP ONLY) PBX/PS911/Shared Tenant | A | MA | 413-750-2400 |
| COSRV | Advantex Communications (Cancelled) | Facility | C | TX | 800-236-1076 |
| COSTC | Costco Wholesale - CANCELLED | 9-1-1 Admin-CPE ALI (9-1-1 Jurisdiction/PSAP ONLY) | C | USA - Nationwide | WA | 425-313-8100 |
| COT | City of Thomasville | CLEC Facility CLEC Reseller VoIP Reseller | A | GA | 229-227-5499 |
| COT91 | City of Thornton | 9-1-1 Admin-CPE ALI (9-1-1 Jurisdiction/PSAP ONLY) | | CO | 720-977-5150 |
| COTAL | City of Tallahassee - CANCELLED | PBX | C | FL | 850-891-8698 |
| COTCC | COTC Connections | CLEC Facility | A | OK | 918-377-2241 |
| COTCO | Central Oklahoma Telephone Co. | ILEC | A | OK | 918-377-2241 |
| COTPA | City of Tampa - CANCELLED | VoIP | C | Tampa | FL | 813-274-8067 |
| COUP | Coupons.com - CANCELLED | 9-1-1 Amin-CPE ALI (9-1-1 Jurisdiction/PSAP ONLY) | C | CA | 650-336-4126 |
| COV | Covina-Valley Unified School District | 9-1-1 Admin-CPE ALI (9-1-1 Jurisdiction/PSAP ONLY) | A | CA | 626-974-7000 |
| COVAD | Covad Communications - CANCELLED | VoIP | C | USA | 800-278-7114 |
| COVE | Verdigrid LLC d/b/a Cove Central Communications | VoIP Reseller VoIP Provider | A | CT | GA | ME | MA | NH | RI | TN | VT | 207-274-2460 |
| COW | City of Waterbury | 9-1-1 Admin-CPE ALI | A | CT | 203-574-6775 |
| COWB | Cellular One Washington/Baltimore (Cancelled) | Carrier | C | MD, VA, DC, WV | 410-712-7725 |
| COWGA | City of Woodstock - CANCELLED | PBX/PS911/Shared Tenant | C | GA | 404-606-4259 |
| COWMA | City of Waltham, Mass. (Cancelled) | PBX | C | MA | 800-835-7656 |
| COX | Cox Communications Inc. | 9-1-1 Admin-CPE ALI (9-1-1 Jurisdiction/PSAP ONLY) | A | USA - Nationwide | 404-269-8831 |
| COXAZ | Cox Communications Inc. | CLEC Facility CLEC Reseller CLEC UNE VoIP Reseller VoIP Provider | A | AZ | 404-269-8375 |
| COXCA | Cox Communications Inc. | CLEC Facility CLEC Reseller CLEC UNE VoIP Reseller VoIP Provider | A | CA | 404-269-8375 |
| COXCB | Cox Communications(Cancelled) | CLEC Reseller, ILEC, PBX/PS911/Shared Tenant, VoIP Reseller, VoIP Provider | C | AZ, AK, OH, OK, RI, VA, CA, CT, FL, GA, KS, LA, NE, NV | 404-449-0946 |
| COXFL | COX COMMUNICATIONS INC. - (CANCELLED) | CLEC Facility CLEC Reseller CLEC UNE VoIP Reseller VoIP Provider | C | FL | GA | 404-269-8375 |
| COXKS | Cox Communications Inc. | CLEC Facility CLEC Reseller CLEC UNE VoIP Reseller VoIP Provider | A | AK | KS | 404-269-8375 |
| COXLA | Cox Communications Inc | CLEC Facility CLEC Reseller CLEC UNE VoIP Reseller VoIP Provider | A | LA | 404-269-8375 |
| COXNE | Cox Communications Inc | CLEC Facility CLEC Reseller CLEC UNE VoIP Reseller VoIP Provider | A | ID | IA | NE | 404-269-8375 |
| COXNV | Cox Communications Inc | CLEC Facility CLEC Reseller CLEC UNE VoIP Reseller VoIP Provider | A | NV | 404-269-8375 |
| COXOK | Cox Communications Inc. | CLEC Facility CLEC Reseller CLEC UNE VoIP Reseller VoIP Provider | A | OK | 404-269-8375 |
| COXRI | Cox Communications Inc. | CLEC Facility CLEC Reseller CLEC UNE VoIP Reseller VoIP Provider | A | CT | RI | 404-269-8375 |
| COXVA | Cox Communications Inc. | CLEC Facility CLEC Reseller CLEC UNE VoIP Reseller VoIP Provider | A | VA | 404-269-8375 |
| COXW | Cox Communications - Wireless - CANCELLED | Wireless/Cellular/PCS | C | USA | 404-499-0946 |
| COYVA | County of York | PBX/PS911/Shared Tenant | A | County of York | 757-897-6239 |
| COZAD | Cozad Telephone Company | ILEC | A | NE | 308-784-4044 |
| CPD | Coppell Police Department - CANCELLED | 9-1-1 Admin-CPE ALI | C | TX | 972-304-3600 |
| CPIC | CITIZENS PROPERTY INSURANCE | PBX/PS911/Shared Tenant | A | FL | 813-465-6211 |
| CPLL | CommPartners LLC - CANCELLED | VoIP | C | NE | 877-297-0926 |
| CPLLC | Chateau Pacific (Cancelled) | CLEC | C | WA | 866-463-6225 |
| CPLS | Cost Plus Communications - CANCELLED | CLEC Facility | C | TX | IL | MI | 866-909-9250 |
| CPLX | Computer Linx | VoIP Reseller VoIP Provider | A | USA - Nationwide | 661-333-6311 |
| CPP | Cal Poly Pomona | 9-1-1 Admin-CPE ALI (9-1-1 Jurisdiction/PSAP ONLY) | A | CA | 909-869-3070 |