| Business | Phone |
| Marconi Communications 15 High Button Ct, Baltimore 21236 | (410) 248-0818 |
| Dlt Telecom Llc 4620 York Rd, Baltimore 21212 | (410) 435-4540 |
| Excellent Choice Communication 1005 Cooks Ln, Baltimore 21229 | (443) 992-5844 |
| Lord Baltimore Capital Corp 6225 Smith Ave, Baltimore 21209 | (410) 580-0897 |
| Shortline Systems Inc 1212 Philco Rd, Baltimore 21237 | (410) 335-8000 |
| Mas Tec 4206 Shannon Dr, Baltimore 21213 | (410) 325-3053 |
| Metropolitan Fiber Systems Inc 6 Saint Paul St, Baltimore 21202 | (410) 547-1341 |
| Paniaguas Enterprises Inc 6400 Frankford Ave # 29, Baltimore 21206 | (410) 485-9327 |
| Atx Telecommunications 809 Glen Eagles Ct # 200, Baltimore 21286 | (410) 821-2900 |
| Resources Group Of America Inc 400 E Pratt St, Baltimore 21202 | (410) 685-6957 |
| Broadwing Commmunications 1200 66th St, Baltimore 21237 | (410) 325-2416 |
| Smartcomm Tele Svc 6127 Twilight Ct, Baltimore 21206 | (410) 866-9151 |
| Cec Communications Mgmt 8602 Inwood Rd, Baltimore 21244 | (410) 655-4801 |
| Tele Message Inc 1190 W Northern Pkwy # 631, Baltimore 21210 | (410) 377-3060 |
| Verizon Communications 323 N Charles St, Baltimore 21201 | (410) 468-0282 |
| Verizon Maryland Inc 1 E Pratt St, Baltimore 21202 | (410) 539-9900 |
| Virtual Network Svc Corp 12 N Calvert St, Baltimore 21202 | (410) 837-2112 |
| Joseph Heimbach Baltimore 21220 | (410) 321-9396 |
| Ker-Telecomm 6000 Old Frederick Rd, Baltimore 21228 | (410) 744-7841 |
| X O Communications Inc 6420 Frederick Rd, Baltimore 21228 | (410) 455-0123 |