| Business | Phone |
| X O Communications Inc 6015 Montrose Rd, Rockville 20852 | (301) 468-5668 |
| Web Telecom Intl Group 10101 Grosvenor Pl, Rockville 20852 | (301) 530-8006 |
| Switch & Data Facilities Co 1680 E Gude Dr, Rockville 20850 | (301) 762-1911 |
| Sykes Communications Systems 1680 E Gude Dr, Rockville 20850 | (301) 808-0818 |
| Startec 1151 Seven Locks Rd, Rockville 20854 | (301) 294-9976 |
| Sonet Solutions 11200 Rockville Pike, Rockville 20852 | (301) 816-9522 |
| Ritenet Corp 1445 Research Blvd # 350, Rockville 20850 | (301) 251-5636 |
| Providence Co 10344 Procera Dr, Rockville 20850 | (240) 453-9300 |
| Essential Technologies 1401 Rockville Pike, Rockville 20852 | (301) 284-3000 |
| G N Engineering Design 4920 Adrian St, Rockville 20853 | (301) 962-1800 |
| Mci 1901 Research Blvd # 160, Rockville 20850 | (301) 777-1509 |