| Business | Phone |
| Sigma-Internet Inc 732 N Diamond Bar Blvd # 112, Diamond Bar 91765 | (909) 861-7500 |
| California Integrated 556 N Diamond Bar Blvd # 301a, Diamond Bar 91765 | (909) 860-3005 |
| E T Micro 20653 Lycomng, Diamond Bar 91765 | (909) 468-1991 |
| Nu Media System Diamond Bar 91765 | (909) 598-8412 |