| Business | Phone |
| Alliance Telecommunications Columbia 21044 | (410) 992-0210 |
| Infiniti Telecom & Tech Inc 9689 Gerwig Ln, Columbia 21046 | (410) 309-4180 |
| Physicians Telephone Answering 1707 L St Nw, Columbia 21046 | (202) 466-1870 |
| Us Lec Of Maryland Inc 6940 Columbia Gateway Dr # 100, Columbia 21046 | (443) 573-1000 |