| Business | Phone |
| Business Radio Products Inc 5714 Industry Ln # D, Frederick 21704 | (301) 694-0041 |
| California Radio 5711 Industry Ln # 6, Frederick 21704 | (301) 698-5696 |
| Hankey's Radio Inc Evergreen Pl & Elm Stamp;, Frederick 21701 | (301) 662-1381 |
| Harris Corp 6476 Forest Hills Ct, Frederick 21701 | (301) 360-9632 |
| Mel-Comm Electronics 6121 Quinn Orchard Rd, Frederick 21704 | (301) 694-8611 |