| Business | Phone |
| A Telecorps 70 Esna Park Dr, Markham L3R 6E7 | (905) 477-0160 |
| Aatel-Midcom Solutions Inc 2600 John St #116, Markham L3R 3W3 | (905) 475-2404 |
| Allnet Communications Inc 2651 John St #6, Markham L3R 2W5 | (905) 477-8329 |
| Avaya Canada Corp 1380 Rodick Rd, Markham L3R 4G5 | (905) 474-6000 |
| Global Access Communications 3400 14th Ave, Markham L3R 0H7 | (905) 415-1134 |
| Headset Doctor 144 Steelcase Rd W, Markham L3R 3J9 | (905) 479-2929 |
| Innings Telecom 1241 Denison St #31, Markham L3R 4B4 | (905) 470-7070 |
| Digicellnet 3255 Highway 7, Markham L3R 3P9 | (905) 305-1067 |
| Sentinel Communications Ltd 99 Longwater Chase, Markham L3R 4A9 | (416) 410-0361 |
| Takson Technology Ltd 250 Cochrane Dr #1, Markham L3R 8E5 | (905) 415-8501 |
| Telephone Depot 7310 Woodbine Ave, Markham L3R 1A4 | (905) 474-2496 |
| Telephone Booth 5000 Highway 7, Markham L3R 4M9 | (905) 947-9862 |
| Telus National Systems 70 Gough Rd, Markham L3R 0E9 | (905) 474-0460 |
| Voicegate Technologies 550 Alden Rd, Markham L3R 6A8 | (905) 479-9669 |
| Voice Gate Corp 550 Alden Rd, Markham L3R 6A8 | (905) 479-5155 |
| Voice Gate Corp 16 Esna Park Dr #5, Markham L3R 5X1 | (905) 513-1403 |
| World Of Communications 40 Delancey Cres, Markham L3P 7E2 | (416) 292-4500 |
| Canadian Communication Prods 3400 14th Ave #1, Markham L3R 0H7 | (905) 470-2056 |
| Engenius Technologies Canada 85 Citizen Crt, Markham L6G 1A8 | (905) 940-8181 |
| Delphi Solutions Inc 7550 Birchmount Rd, Markham L3R 6C6 | (905) 513-4600 |
| Dial Tone Communications Inc 2900 John St, Markham L3R 5G3 | (905) 470-1894 |