| Business | Phone |
| All Tronics Inc 1287 Rankin Dr, Troy 48083 | (248) 577-4200 |
| Bcs Networks Inc 275 E Big Beaver Rd, Troy 48083 | (248) 619-3990 |
| Digital Data & Voice Solutions 1729 E 14 Mile Rd, Troy 48083 | (248) 583-6558 |
| Executone Telecommunications 839 Ridgewood Rd, Troy 39157 | (601) 956-6203 |
| Groesbeck Communications 2044 Virginia Dr, Troy 48083 | (248) 528-2822 |
| Groesbeck Telecommunications 2044 Virginia Dr, Troy 48083 | (586) 979-9260 |
| Metroline Inc 2250 Meijer Dr, Troy 48084 | (248) 288-7000 |
| Pdi Svc 2858 Samuel Dr, Troy 48083 | (248) 689-9235 |