| Business | Phone |
| Standards & Calibrations 1223 Rand Rd, Des Plaines 60016 | (847) 296-7121 |
| Sphere Connections 570 E Northwest Hwy, Des Plaines 60016 | (847) 795-8670 |
| Raytheon Technical Svc Co 10600 W Higgins Rd 401, Des Plaines 60018 | (847) 699-8400 |
| Wide Area Video Surveillance 3158 S River Rd, Des Plaines 60018 | (847) 627-5225 |