1. 3CX
2. 8x8 Inc.
3. astTECS Communications Pvt. Ltd.
4. AT&T Inc.
5. Avaya LLC
6. Barracuda Networks Inc.
7. CallHippo
8. Cisco Systems Inc.
9. D-Link Corporation
10. Deutsche Telekom AG
11. DialerHQ
12. DIALPAD Inc.
13. DigitalWell
14. Epygi Technologies LLC
15. Freshworks Inc.
16. Google LLC by Alphabet Inc.
17. GoTo Technologies USA Inc.
18. Lingo Telecom
LLC
19. Microsoft Corporation
20. Mitel Networks Corporation
21. Nextiva Inc.
22. Ooma Inc.
23. Oracle Corporation
24. PortaOne Inc.
25. PortSIP Solutions Inc.
26. RingCentral Inc.
27. SoftBank Group Corp.
28. Tata Teleservices Limited
29. The Real PBX Limited
30. TollFreeForwarding.com
31. TPx Communications
32. UniTel Voice
LLC
33. Verizon Communications Inc.
34. VirtualPBX.Com Inc.
35. Vodafone Group PLC
36. Vonage Holdings Corp. by Telefonaktiebolaget LM Ericsson
37. Wildix O?
38. Xiamen Yeastar Information Technology Co. Ltd.
39. Zoom Video Communications Inc.