# | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z
| Company Name | Contact Address | Phone |
| Calix | Mitch Flemming 1035 N McDowell Blvd Petaluma California 94954 | 707-766-3000 |
| CoBank | Tanya Sullivan 5500 S Quebec Street Denver Colorado 80111 | 800-542-8072 |
| Communications Data Group | Bobbie McKay 102 S Duncan Road Champaign Illinois 61822 | 217-355-7100 |
| Communications Software Consultants | Michael Donnelly 96 Thompson Hill Road Rennselaer New York 12144 | 518.431.7500 |
| Compass Consultants Inc. | Jason G. Dale 150 2nd Street, S.W. Perham Minnesota 56573 | 218-346-3600 |
| Conklin-Intracom | Dave Hunt 11360 Technology Circle Johns Creek Georgia 30097 | 770-295-2600 |