| Business | Phone |
| And Cable Products Inc 1460 Washington Blvd # A103, Concord 94521 | (925) 672-3005 |
| And Network Svc 1460 Washington Blvd # A103, Concord 94521 | (925) 672-3005 |
| Audio Design 4743 Clayton Rd # 3, Concord 94521 | (925) 680-7476 |
| H J Hirtzer & Assoc Inc 1630 Sally Ride Dr, Concord 94520 | (925) 682-8744 |
| Kyocera Technology Development 1855 Gateway Blvd # 400, Concord 94520 | (925) 849-3300 |