By adding the Secure Voice feature and associating it with a seat that uses a compatible device, calls made and received on that device are encrypted to provide a secure connection. The message is encrypted at the origin and decrypted at the cloud. If the other end also uses some kind of encryption technology, that will engage at the cloud to their end. For end-to-end encryption, both parties would need a product such as Secure Voice.
Poly 150, 250, 350, 450
Poly Trio conference phones
Yealink SIP-T33G
Yealink SIP-T43U
Yealink SIP-T46U
Yealink SIP-T53W
Yealink SIP-T54W
Yealink SIP-T57W
When the product has been added to your service, you will assign it to a line in the Locations section of the Customer Admin Portal.
That line is now secure to the cloud.