| Business | Phone |
| Thm Management Diamond Bar 91765 | (909) 860-3745 |
| Answer Network Diamond Bar 91765 | (909) 861-9444 |
| Everaccent Communications 1200 S Diamond Bar Blvd # 206, Diamond Bar 91765 | (909) 396-7488 |
| Urban Telecommunication 2660 Crooked Creek Dr, Diamond Bar 91765 | (909) 468-1133 |