| Business | Phone |
| Concord Voice & Data 4307 Arleda Ln, Concord 94521 | (925) 363-4940 |
| Diablo Communications 4425 Treat Blvd # C, Concord 94521 | (925) 685-3600 |
| Metro Telecom Wire & Cable Po Box 271531, Concord 94527 | (925) 229-8394 |
| Netcomm Solutions Concord 94520 | (925) 473-9912 |
| New Dimension Telecom Po Box 6440, Concord 94524 | (925) 687-7224 |
| Pop Bell Concord 94520 | (925) 363-4940 |