| Business | Phone |
| Z Tech Corp 1803 Research Blvd # 301, Rockville 20850 | (301) 315-2800 |
| Computer Institute 1335 Rockville Pike # 3, Rockville 20852 | (301) 424-0044 |
| Officepro Inc 12250 Rockville Pike # 250, Rockville 20852 | (301) 468-3312 |
| Harmony Computer Institute 15209 Frederick Rd, Rockville 20850 | (301) 424-7012 |