| Business | Phone |
| American Telephone Communicate 102 S Frederick Ave, Gaithersburg 20877 | (301) 670-7999 |
| B G Communications Inc 923 Beacon Square Ct, Gaithersburg 20878 | (301) 548-9555 |
| Teldata Communications Inc 19211 Chennault Way # A, Gaithersburg 20879 | (301) 670-0122 |
| Bennet Communications 7609 Airpark Rd # H, Gaithersburg 20879 | (301) 963-3257 |
| Comlink Telecommunications 19225 Orbit Dr, Gaithersburg 20879 | (301) 519-4200 |
| Eka Systems Inc 444 N Frederick Ave, Gaithersburg 20877 | (301) 990-3450 |
| Mid Atlantic Telephone Inc 16021 Industrial Dr # 9, Gaithersburg 20877 | (301) 424-8228 |