| Business | Phone |
| Cardinal Systems 211 W Patrick St, Frederick 21701 | (301) 228-2744 |
| Data Management Svc 145 W Patrick St, Frederick 21701 | (301) 293-6188 |
| Expo Exchange 1888 N Market St, Frederick 21701 | (301) 662-9400 |
| Southeastern Computer Conslnt 3 Hillcrest Dr # 201, Frederick 21703 | (301) 695-5311 |