Better quality, more natural, encrypted calls are available using…
But not all Voice over internet Protocol (VoiP) technology stacks are the same.
Basic unencrypted SIP+UDP is fine for Hi-Definition G.722 audio codec support on most local networks. Enabling G.722 often improves call quality considerably on any modern desk phone that was previously set for G.711. And more SIP trunk and cell phone providers are increasingly offering better levels of codec support, particular when calls remain in-network from customer-to-customer on the same carrier.
You can do the same with open source software in modern business phone systems like ASTERISK®.
You can actually achieve even better sounding and more secure communications.
And you’ll know its working with modern desk phones that display various logos; such as padlocks for encryption, or HD/HiQ logos when G.722 is activated.
Open standards choices for encrypted wider-band audio/visual VoiP PBX solutions in 2019 include:
|Stacks||Connect||Methods & Materials|
|SIP + UDP + VPN||Employees, Contractors||Desk phones, firewalls, PCs, cells.|
|SIP + TCP + TLS||Carriers, Customers||SIP trunks, lots of desk phones.|
|WebRTC + HTTPS||General Public Guests||Cross-platform web browsers.|
|IAX + UDP||PBXes behind NATs||Pre-shared symmetric keys.|
|T1 + PRI + ISDN*||Remote Corporate PBXes||VPN over bonded B-Channels.|
|POTS*||Random Land Lines||Maybe Morsecode in ASTERISK.|
Combine these with Bring Your Own Bandwidth (BYOB) and sufficient Quality-of-Service (QoS) on your devices/clouds and you can independently pile on carriers across circuits at multiple locations, intelligently blending systems to support remote connectivity and better call quality.
*NOTE: Both stacks T1 + PRI + ISDN and POTS as hand-offs to PBXes could be lossy/jittery VoiP transactions on the Carrier side of the network, so they got included. Either way, the pure VoiP solutions at the top of the list are much preferred.
**EDIT: April 2019 - with a nicer title and open standards remark.