| CoID | Company | Type | Status | States Served | 24X7 Phone |
| AAANE | AAA Northern New England | ILEC | A | ME | NH | VT | 207-831-4575 |
| AACC | Anne Arundel Community College | ILEC Wireless/Cellular/PCS VoIP Provider | A | MD | 410-777-1818 |
| AACOU | Anne Arundel County Government | PBX/PS911/Shared Tenant | A | MD | 410-222-8610 |
| AARNG | Arkansas Army National Guard - CANCELLED | CLEC Faciility | C | USA | 501-590-5735 |
| AATI | Spectrotel (formerly Plan B Communications) | Facility | A | NY | 888-773-9722 |
| ABAND | Airband Communications - CANCELLED | VoIP Provider | C | USA | 800-843-2263 |
| ABCWO | AbbVie Bioresearch Center - CANCELLED | PBX/PS911/Shared Tenant | C | MA | 508-849-2604 |
| ABIOS | Applied Bio Systems - CANCELLED | ILEC | C | CA | 480-719-8556 |
| ABMC | Advocate BroMenn Medical Center | PBX/PS911/Shared Tenant | A | IL | 309-268-2580 |
| ABN | Bestline Communications LP | CLEC Facility CLEC Reseller CLEC UNE | A | TX | 5123289095 |
| ABQ26 | Net-Tel Corporation (Cancelled) | CLEC | C | NY, Chicago, Los Angeles | 800-561-2903 |
| ABS | Adelphia Business Solutions (Cancelled) | CLEC | C | PA | 800-292-2314 |
| ABSTX | ABS TALKX INC | VoIP Reseller | A | USA - Nation Wide | 516-445-4000 |
| ABWA | City of Aberdeen | 9-1-1 Admin-CPE ALI (9-1-1 Jurisdiction/PSAP ONLY) PBX/PS911/Shared Tenant | A | WA | 360-533-8765 |
| AC001 | Aureon Communications L.L.C. (formally Alliance Connect) | CLEC Reseller VoIP Reseller VoIP Provider | A | IL | IA | MN | MO | NE | 888-638-4671 |
| ACAA | Allegheny County Airport Authority | VoIP | A | Pittsburgh International Airport | 800-773-7911 |
| ACAD | Acadia National Park | VoIP Provider | A | ME | 207-610-0648 |
| ACAT | Aventure Communication & Technology - CANCELLED | CLEC Facility | VoIP | C | IA | NE | SD | 712-255-3085 |
| ACC | Akron Canton Communications (Cancelled) | Reseller | C | OH | 330-699-5699 |
| ACC14 | America's Call Center | PBX/PS911/Shared Tenant | A | USA - Nationwide | 904-224-2000 |
| ACC21 | ACC Telecom | VoIP Reseller | A | USA - Nationwide | 910-471-3057 |
| ACCB | Arrowhead Communications Corp. | LEC | A | US | 800-992-8857 |
| ACCEN | Kansas Information Technologies LLC dba ACCENTLOGIC | VoIP Reseller | A | USA - Nationwide | 913-225-7796 |
| ACCES | Accessible Wireless (CANCELLED) | Wireless | C | CA, AZ | 949-439-2888 |
| ACCIP | Accipiter Communications Inc. | ILEC | A | AZ | 623-455-4500 |
| ACCNT | ACCENT COMMUNICATION SERVICES INC | VoIP Provider | A | USA - Nationwide | 740-548-7378 |
| ACDC | Adept Communication and Data Company Inc | VoIP Reseller VoIP Provider | A | USA - Nationwide | 240-674-9422 |
| ACDEL | ACD Telecom | Facility | A | MI | 517-999-9999 |
| ACE | ACE Hardware Corporation | PBX/PS911/Shared Tenant | A | IL | 815-872-3000 |
| ACECM | Ace Telephone Association dba AcenTek | ILEC | A | MN | IA | 507-896-3192 |
| ACEIN | ACE Innovative Networks | VoIP Provider | A | USA | 212-931-9034 |
| ACELK | Ace Link Telecommunciations Inc dba AcenTek | CLEC Facility | A | MN | 507-896-3192 |
| ACEMI | Ace Telephone Company of MI Inc | ILEC | A | MI | 507-896-3107 |
| ACG | Advanced Communicatons Group (Out of Business) | CLEC | C | TX, KS, MO, OK | 877-333-2555 |
| ACG01 | Arlington County | PBX/PS911/Shared Tenant | A | VA | 703-558-2222 |
| ACG20 | Agility Communications Group | PBX/PS911/Shared Tenant VoIP Reseller VoIP Provider | A | USA - Nationwide | 972-715-8900 Option 2 |
| ACI | ALLTEL Communications, Inc. (Cancelled - see WINC) | Facility | C | ALL | 800-392-0186 |
| ACINC | AudioCodes Inc | VoIP Reseller | A | USA - Nationwide | 800-735-4588 |
| ACIW | Alltel Communications Inc. - CANCELLED | Wireless/Cellular/PCS | C | ALL | 501-607-4594 |
| ACME | Acme Communications Inc. | CLEC Facility | A | IN | 219-879-6600 |
| ACN61 | Arrival Communications (CANCELLED) | CLEC Facility | C | CA | 800-851-6705 |
| ACNDP | All Communication Services LLC | VoIP Provider | A | USA - Nationwide | 866-662-6645 |
| ACOLL | Austin College(Cancelled) | CLEC Facility, ILEC, VoIP | C | TX | 903-813-2555 |
| ACOM | ACOM LLC | VoIP Provider | A | VA | 540-631-5460 |
| ACOMM | Access Communications, LLC (INACTIVE) | CLEC Reseller, CLEC UNE | C | FL | 904-463-6500 |
| ACONA | Accoona Global LLC | VoIP Reseller VoIP Provider | A | USA - Nation Wide | 682-400-4800 |
| ACPNY | AdvantageCare Physicians | PBX/PS911/Shared Tenant | A | NY | 646-680-1302 |
| ACPS | Appomattox County Public Schools | VoIP Provider | A | VA | 434-664-8984 |
| ACS | Arvig Communication Systems, Inc. (INACTIVE) | LEC, CLEC | C | MN | 218-346-5500 |
| ACSAK | Alaska Communications Systems - CANCELLED | ILEC VoIP Provider | C | AK | 907-564-1642 |