Is a cloud PBX any different from hosted VoIP or a cloud phone system?
Summary
Not in any way that matters. All three names describe a phone system whose switchboard runs in a provider's data center and that your team reaches over the internet, and no law or standard separates them. The real differences between products lie in how each one connects to the regular phone network. The term that does mean something else is SIP trunk, which is a line into a PBX, not a PBX.
What the PBX part means
A PBX, or private branch exchange, links internal extensions, sends incoming calls to the right person or department, and lets staff place outside calls. Transferring a caller to a colleague's extension is a PBX job.
It used to be a box on site wired to phone company lines. In a cloud PBX, the provider runs it. Comcast Business calls its VoiceEdge product a cloud-hosted PBX service and says it delivers many of the benefits of an onsite PBX without additional hardware costs or storage space. The feature list reads like an office PBX: automated attendants, hunt groups, call hold and transfer, call park and pickup. Desk phones are leased for an extra monthly fee.
Hosted VoIP, cloud phone, cloud PBX
If the three names lean anywhere, cloud PBX points at the switchboard features, hosted VoIP at the fact that the provider operates it, and cloud phone at its being an internet service. The technology underneath is the same.
Federal 911 rules don't draw the line either. The FCC's definition of a multi-line telephone system lists network-based VoIP systems next to on-premises PBXs, so a cloud PBX has to meet Kari's Law: direct 911 dialing without a prefix, and a notification when someone dials 911.
SIP trunks are something else
A SIP trunk is a set of virtual phone lines for making and receiving calls over the internet. 3CX puts the distinction neatly: the IP PBX is the phone system, and SIP trunking is the service that connects it to outside networks. Keeping your own PBX and moving its outside lines to SIP trunks leaves the maintenance with you. Moving the PBX itself to the cloud hands it to the provider.
Where cloud PBXs really differ
Microsoft Teams Phone offers four ways to connect to the public phone network:
- Calling Plan, with Microsoft as your phone company. It needs a Teams Calling Plan license.
- Operator Connect, through a certified third-party carrier you contract with.
- Teams Phone Mobile, where a certified mobile operator's SIM number doubles as the user's Teams number.
- Direct Routing, with any carrier you like, through a session border controller (SBC) that you, an integrator, or a service provider manage.
Zoom Phone provides calling service in 49+ countries and also supports bring your own carrier (BYOC), and Zoom says you can transfer your existing business number. Two products at a similar price can differ sharply on whether you keep your number and your current carrier.
Sources
- business.comcast.com/learn/phone/voiceedge-virtual-pbx
- ecfr.gov/current/title-47/chapter-I/subchapter-A/part-9/subpart-A/section-9.3
- fcc.gov/mlts-911-requirements
- aws.amazon.com/what-is/sip-trunking
- 3cx.com/pbx/sip-trunking
- learn.microsoft.com/en-us/microsoftteams/pstn-connectivity
- zoom.com/en/products/voip-phone
Related on this site
- What happens behind the scenes when someone calls a cloud phone number?
- Should you own your phone system's PBX or let a cloud provider run it?
- Is SIP just another word for VoIP?
- Is the $10 Microsoft Teams Phone license enough to call regular phone numbers?
- Which Zoom Phone plan do you need if all three include the same calling?
- Will 911 know where you are if you call from a VoIP phone?
Written by Kaz (pen name). Figures are copied from providers' published pricing pages on the dates shown. We have not used these products. Corrections: contact form.