| Business | Phone |
| American Technologies 1250 Pine St # 105, Walnut Creek 94596 | (925) 944-0777 |
| Davis & Hanley Network Sltns Walnut Creek 94596 | (925) 935-4002 |
| International Totalizing Systs Walnut Creek 94596 | (925) 945-0500 |
| Interstar Communications Group Walnut Creek 94596 | (925) 210-0202 |
| Klw Co 1630 N Main St # 442, Walnut Creek 94596 | (925) 933-6399 |
| Sure Com Solutions 1776 Botelho Dr # 103, Walnut Creek 94596 | (925) 938-4960 |
| Telecom Systems Solutions 405 Sutcliffe Pl, Walnut Creek 94598 | (925) 930-7973 |
| Tetra Tech Wahlen 1255 Treat Blvd, Walnut Creek 94597 | (925) 472-3540 |