| Business | Phone |
| Alpha Controls & Instrmntn 361 Steelcase Rd W #5, Markham L3R 3V8 | (905) 477-2133 |
| Anderson Controls 395 Cochrane Dr, Markham L3R 9R5 | (416) 766-4195 |
| Aquatronix Inc 70 Gibson Dr, Markham L3R 4C2 | (905) 475-8082 |
| Johnson Controls Ltd 7400 Birchmount Rd, Markham L3R 5V4 | (905) 475-7610 |
| Mamac Systems Canada Ltd 155 Mcintosh Dr, Markham L3R 0N6 | (905) 474-9215 |
| Pro Kontrol 500 Alden Rd, Markham L3R 5H5 | (905) 475-9888 |
| Process Instruments & Cmpnnts 441 Esna Park Dr, Markham L3R 1H7 | (905) 513-7653 |
| Baker Instruments Ltd 395 Cochrane Dr, Markham L3R 9R5 | (905) 947-1771 |
| Trillium Measurement & Control 2600 John St, Markham L3R 3W3 | (905) 305-7790 |
| Chartwell Electronics Inc 140 Duffield Dr, Markham L6G 1B5 | (905) 513-7100 |