| Business | Phone |
| Telephone Support Systems Inc 26450 Haggerty Rd, Farmington 48331 | (248) 489-0000 |
| Desi 20708 Orchard Lake Rd, Farmington 48336 | (734) 785-5900 |
| Electronics Unlimited 25401 Power Rd, Farmington 48336 | (248) 471-0176 |
| High-Tech Telephone Systems 24067 Research Dr, Farmington 48335 | (248) 473-5533 |