1. MITEL NETWORKS CORPORATION
2. ALCATEL-LUCENT
3. AT & T INC.
4. AVAYA INC.
5. CISCO SYSTEMS INC.
6. HEWLETT PACKARD ENTERPRISE
7. IBM CORPORATION
8. MICROSOFT CORPORATION
9. SIEMENS ENTERPRISE COMMUNICATIONS (UNIFY INC.)
10. VERIZON COMMUNICATION
11. NEC CORPORATION
12. PLANTRONICS INC.
13. RING CENTRAL INC.
14. CONNECT SOLUTIONS INC.
15. FUZE INC.