| Business | Phone |
| Customer 500176328 1 S Dearborn St, Chicago 60603 | (312) 263-0466 |
| Realcom Office Communications 180 N Stetson Ave, Chicago 60601 | (312) 946-8870 |
| Loop Telecommunication Inc 300 S Wells St, Chicago 60606 | (312) 341-6509 |
| Realcom Office Communications 233 S Wacker Dr, Chicago 60606 | (312) 707-8999 |
| Vtel Corp 200 S Wacker Dr 3100, Chicago 60606 | (312) 444-2042 |
| Information Command 411 W Ontario St 225, Chicago 60610 | (312) 245-1111 |
| Remesas Hispanos Americanos 3145 W Logan Blvd, Chicago 60647 | (773) 252-5501 |
| United Communications Systems 500 W Madison St 411, Chicago 60661 | (312) 225-5663 |
| Strides Telecommunication Svc 150 N Michigan Ave 430, Chicago 60601 | (773) 221-0200 |
| Cypress Communications 181 W Madison St, Chicago 60602 | (312) 332-0756 |
| Harders Assoc 104 S Michigan Ave, Chicago 60603 | (312) 782-0966 |
| Victoria's Court Reporting Svc 29 S La Salle St 200, Chicago 60603 | (312) 443-1025 |
| Brtel Chicago 60605 | (312) 386-1223 |
| Ixc Communications 720 S Michigan Ave, Chicago 60605 | (312) 986-1715 |
| Munimae Midlands 111 S Wacker Dr, Chicago 60606 | (312) 443-0134 |
| National Telephone Enterprises 20 N Wacker Dr, Chicago 60606 | (312) 263-7608 |
| Rockefeller Group Tlcmmnctns 200 W Madison St, Chicago 60606 | (312) 263-8818 |
| Conecta Communications 1746 W 47th St, Chicago 60609 | (773) 890-3935 |
| A T & T 1234 N Sedgwick St, Chicago 60610 | (312) 951-7611 |
| K-Consulting Chicago 60610 | (312) 482-9333 |
| Summit Communications Inc 2901 N Fairfield Ave, Chicago 60618 | (773) 866-0300 |
| Talk America Inc 550 Warnick Ave, Chicago 60618 | (312) 546-4727 |
| P J Multiservice Llc 3755 W 26th St, Chicago 60623 | (773) 521-9700 |
| U U Net 8755 W Higgins Rd, Chicago 60631 | (773) 693-1719 |
| Sertel South Chicago 5347 W 53rd Pl, Chicago 60638 | (773) 582-4528 |
| Marathon Amusement 4201 W Wrightwood Ave 100, Chicago 60639 | (773) 486-9400 |
| Service Amusement 4201 W Wrightwood Ave, Chicago 60639 | (773) 736-6000 |
| Advance International Phone 4321 N Knox Ave, Chicago 60641 | (773) 942-8600 |
| International Video Conference 350 N Orleans St 1384, Chicago 60654 | (773) 278-8300 |
| Premiere Conferencing 1154 W Newport Ave, Chicago 60657 | (773) 325-9498 |
| Ravago & Assoc 5757 N Lincoln Ave, Chicago 60659 | (773) 989-7716 |
| Telephone Information 6145 N Sheridan Rd, Chicago 60660 | (773) 777-7775 |