| Business | Phone |
| Rialto Production Inc 1222 North Ave, Baltimore 21227 | (410) 523-0979 |
| Keystone Electric Co Inc 2807 Annapolis Rd, Baltimore 21230 | (410) 539-1730 |
| Dial Electronics 3910 Vero Rd, Baltimore 21227 | (443) 568-0189 |
| Lemax Systems 9500 Pulaski Hwy, Baltimore 21220 | (410) 391-5800 |