| Business | Phone |
| Mci 2175 N California Blvd # 700, Walnut Creek 94596 | (925) 951-2600 |
| Tele Management Technologies 2700 Ygnacio Valley Rd # 250, Walnut Creek 94598 | (925) 946-9800 |
| A-1 Data Inc Walnut Creek 94596 | (925) 680-6900 |
| All Business Communications 1870 Olympic Blvd, Walnut Creek 94596 | (925) 383-5983 |
| Executive Phone Svc Walnut Creek 94596 | (925) 946-0169 |
| Mci 3075 Citrus Cir, Walnut Creek 94598 | (925) 935-1507 |
| Telecommunications Co Walnut Creek 94596 | (925) 937-5422 |