| Business | Phone |
| Integrated Tel Svc 900 Jorie Blvd, Oak Brook 60523 | (630) 990-1650 |
| Litel Telecommunication 2021 Midwest Rd, Oak Brook 60523 | (630) 953-8626 |
| Sbc Oak Brook 60523 | (630) 954-5808 |
| Sei Information Technology 1520 Kensington Rd 310, Oak Brook 60523 | (630) 413-5050 |
| Sunesys 2625 Butterfield Rd 138, Oak Brook 60523 | (630) 571-2570 |
| Telecomm Strategies Inc 125 Windsor Dr 105, Oak Brook 60523 | (630) 573-1417 |
| X O Communications Inc 810 Jorie Blvd 200, Oak Brook 60523 | (630) 371-3100 |