| Business | Phone |
| Adi 8 Metropolitan Ct # 8-9, Gaithersburg 20878 | (301) 990-9790 |
| C & C Homation Systems Inc 19120 Harkness Ln, Gaithersburg 20879 | (301) 670-9775 |
| Satellite Industries 101 Cherrywood Ter, Gaithersburg 20878 | (301) 840-5420 |
| Security Network Inc 101 Chestnut St # 200, Gaithersburg 20877 | (301) 670-2882 |
| Securitylink From Ameritech 11 Firstfield Rd, Gaithersburg 20878 | (301) 840-2200 |
| Proline Security Systs 209 Edison Park Dr, Gaithersburg 20878 | (301) 840-8004 |
| Premier Security Po Box 3623, Gaithersburg 20885 | (301) 840-3477 |
| Glessner Alarm & Comm 5 N Frederick Ave, Gaithersburg 20877 | (301) 990-3060 |
| Guardian Protection Svc Inc 8625 Grovemont Cir, Gaithersburg 20877 | (301) 330-1399 |