| Business | Phone |
| Communications Products & Svc 9515 Gerwig Ln # 102, Columbia 21046 | (410) 312-5200 |
| Conectiv Communications 8335 Guilford Rd, Columbia 21046 | (410) 309-4393 |
| D & J Communications 6362 Wind Rider Way, Columbia 21045 | (443) 285-0046 |
| Fuse Communications 10630 Little Patuxent Pkwy, Columbia 21044 | (410) 997-6363 |
| Interline Communication Svc 9140 Guilford Rd # A, Columbia 21046 | (301) 725-4447 |
| National Communications Ntwrk 10480 Little Patuxent Pkwy, Columbia 21044 | (410) 740-8781 |
| Network Communication Tech 5840 Banneker Rd, Columbia 21044 | (240) 554-0430 |
| Pmb Communications 7236 Riding Hood Cir, Columbia 21045 | (301) 621-8401 |
| Prism Communications Inc 6990 Columbia Gateway Dr, Columbia 21046 | (410) 953-0200 |
| Usa Mobility Inc 9030 State Route 108, Columbia 21045 | (410) 720-0040 |
| Wiltel Communications Syst Inc 7130 Columbia Gateway Dr, Columbia 21046 | (410) 312-2800 |