| Business | Phone |
| D-Tech Baltimore 21225 | (410) 636-5996 |
| Jac Communications 6908 Eastern Ave, Baltimore 21224 | (410) 288-5517 |
| Allied Telephone & Data 7604 Babikow Rd, Baltimore 21237 | (410) 574-3300 |
| Telecommunications Concepts 201 N Charles St, Baltimore 21201 | (410) 435-1111 |
| Westbury Communication Systems Baltimore 21206 | (410) 488-8883 |