| CoID | Company | Type | Status | States Served | 24X7 Phone |
| APU | Azusa Pacific University - CANCELLED | PBX/PS911/Shared Tenant | C | CA | 626-815-3898 |
| APW | Altmar Parish Williamstown Central School District | Other | PS/ALI or Private Switch | A | NY | 800-773-7911 |
| AQMD | South Coast Air Quality Management District | 9-1-1 Admin-CPE ALI (9-1-1 Jurisdiction/PSAP ONLY) | A | CA | 909-718-9097 |
| ARAMK | ARAMARK Corporation - CANCELLED | PBX/PS911/Shared Tenant | C | Philadelphia | PA | 215-238-3001 |
| ARBIT | NIELSEN/ARBITRON | PBX/PS911/Shared Tenant | A | MD | 410-312-8000 |
| ARBL | Arbella Mutual Insurance Company | ILEC | A | CT | MA | 617-328-2525 |
| ARBRS | Arbros Communications, Inc. (Cancelled) | Facility | C | ALL | 877-427-2767 |
| ARC | ARC Networks dba InfoHighway Communications(Cancelled) | Reseller | C | CT | 888-272-6389 |
| ARCAD | Arcadia Telephone Cooperative - CANCELLED | ILEC | C | IA | 712-689-2238 |
| ARCOR | Antero Resources Corporation | 9-1-1 Admin-CPE ALI (9-1-1 Jurisdiction/PSAP ONLY) | A | CO | OH WV | 303-357-7310 |
| ARE | Arena One LLC | VoIP Provider | A | USA | 212-231-9600 |
| ARFRE | Airadigm Communications - CANCELLED | Wireless/Cellular/PCS | C | WI | 920-707-4357 |
| ARKDN | NTT Cloud Communications US Inc. | Video Relay Service VoIP Provider Other (must identify below) | Conference Services and Cloud Voice | A | USA - Nation Wide | 866-922-9566 |
| ARLLN | Arialink Telecom - CANCELLED | CLEC Facililty | CLEC Reseller | CLEC UNE | VoIP Reseller | VoIP Provider | C | MI | 517-492-1350 |
| ARMSE | ARCH Medical Solutions - Seabrook | PBX/PS911/Shared Tenant | A | USA - Nationwide | 603-474-1919 |
| ARMST | Armstrong Utilities (CANCELLED) | PBX | C | PA | 724-899-2211 |
| ARNG | Arkansas Army National Guard - CANCELLED | CLEC Facility | C | USA-Nation Wide AR | 501-590-5735 |
| ARNG1 | Vermont Army National Guard (CANCELLED) | PBX | C | VT | 802-338-3050 |
| ARORA | Aurora Communications Inc c/o Wisper ISP LLC | CLEC Facility VoIP Provider | A | MO | 618-206-4190 |
| ARPS | Amherst Regional Public Schools | Facility | A | MA | 413-362-1810 |
| ART | Artisan Communications (CANCELLED) | VoIP | C | KS | 866-733-8878 |
| ARTCH | AirTouch Communications (Cancelled) | ILEC | C | WA, OR, ID, UT, CO, AZ, NM, NE, WY, ND, MN, IA | 800-445-5514 |
| ASCC | Asnuntuck Community College - CANCELLED | VoIP | C | CT | 413-829-1977 |
| ASD16 | Arlington School District | 9-1-1 Admin-CPE ALI (9-1-1 Jurisdiction/PSAP ONLY) | A | USA - Nationwide | 360-913-7005 |
| ASI | Asset Sentinel Inc. (Out of Business) | PBX | C | USA | 612-934-2655 |
| ASPEN | Aspen Datacom (Cancelled) | Facility | C | IL | 773-878-3161 |
| ASPRS | Aspirus Wausau Hospital | Cable Digital Internet Protocol Relay Provider VoIP Provider | A | MI | WI | 715-847-2121 |
| ASSOC | Associated Bank - CANCELLED | 9-1-1 Admin-CPE ALI | C | WI | 715-345-4600 |
| ASTAC | Arctic Slope Telephone Association Coop Inc | ILEC Wireless/Cellular/PCS | A | AK | 877-751-5068 |
| ASTCO | Astro Telecommunications LLC | CLEC Facility CLEC Reseller VoIP Reseller VoIP Provider | A | USA - Nationwide | 833-462-7876 |
| ASTND | Astound Broadband LLC - CANCELLED | CLEC Facility | C | CA | OR | WA | 866-928-3123 |
| ASTRO | AstroTel, Inc. (INACTIVE) | CLEC Facility | C | FL | 877-833-2453 |
| ASU | Angelo State University - CANCELLED | VoIP Provider | C | TX | 325-942-2911 |
| ASUMP | Assumption College | PBX | A | MA | 508-767-7000 |
| AT&T | AT&T | CLEC Facility | A | USA - Nationwide | 888-249-4980 |
| ATBLS | AT&T | CLEC Reseller | A | CA | 800-275-0014 |
| ATC | Alma Telephone Company Inc. | Facility | A | GA | 912-632-5911 |
| ATC83 | Advantage Telephone Communications | VoIP Provider | A | USA - Nationwide | 281-435-6348 |
| ATCID | ATC Communications Inc. | ILEC | A | ID | 208-673-5335 |
| ATCMD | Armstrong Telephone Company - Maryland | ILEC | A | MD | 877-277-5709 |
| ATCN | Armstrong Telephone Company - North | ILEC | A | PA | 877-277-5709 |
| ATCND | Armstrong Telephone Co Northern Div. | ILEC | A | WV | 877-277-5709 |
| ATCNE | ATC Communications | Facility | A | NE | 308-962-8400 |
| ATCNY | Armstrong Telephone Company | ILEC | A | NY | 877-277-5709 |
| ATCO | Ardmore Telephone Company Inc. | ILEC VoIP Reseller | A | AL | TN | 270-856-1033 |
| ATCPA | Armstrong Telephone Company - PA | ILEC | A | PA | 877-277-5709 |
| ATCTC | American Telephone Company | CLEC Facility CLEC Reseller VoIP Reseller VoIP Provider | A | USA - Nation Wide | 888-943-8282 |
| ATCWV | Armstrong Telephone Company - WV | ILEC | A | WV | 877-277-5709 |
| ATEL | Adams TelSystems Inc. | CLEC Facility CLEC UNE VoIP Reseller VoIP Provider | A | IL | 217-696-4411 |
| ATG | ATG Communications LLC | VoIP Reseller VoIP Provider | A | USA - Nation Wide | 706-823-1449 opt 2 |