Updated November 2026
The short version
- Hosted PBX gives you a full business phone system without hardware to maintain.
- UCaaS adds meetings, chat and presence from the same provider.
- If you already use Zoom or Microsoft Teams for meetings and chat, a hosted phone system that works alongside them may be all you need.
What is a cloud phone system?
A cloud phone system runs your business calling from the provider's network instead of equipment in your office. Calls travel over your internet connection, and staff use desk phones, a softphone app on a computer or smartphone, or both. Hosted PBX, hosted VoIP and cloud PBX are all names for this setup.
What is a hosted PBX?
A PBX (private branch exchange) is the system that routes calls inside a business: extensions, transfers, menus and voicemail. Traditionally it was a box in a closet. With a hosted PBX, the provider runs it for you and handles maintenance and updates.
5x5 business VoIP works this way. It includes an auto attendant, voicemail to email, call transfer and forwarding, and a softphone app, with unlimited calling at a flat monthly rate within the terms of your service agreement.
What is UCaaS?
Gartner defines UCaaS as a cloud-delivered subscription service that combines business telephony with collaboration tools such as messaging and meetings. Beyond calling, a UCaaS platform typically includes video meetings, team chat, presence (seeing who is available) and apps that work across desk phones, computers and mobiles.
The provider owns and runs the platform, and you pay a recurring monthly subscription.
Key differences at a glance
- What it covers
- Hosted PBX: Business phone calls
- UCaaS: Phone calls plus meetings, messaging and presence
- Who runs it
- Hosted PBX: The provider
- UCaaS: The provider
- Equipment on site
- Hosted PBX: Desk phones, a softphone app or both
- UCaaS: Desk phones, apps on computers and mobiles
- Meetings and chat
- Hosted PBX: From the tools you already use, such as Zoom or Teams
- UCaaS: Included in the same platform
- Good fit when
- Hosted PBX: You want a reliable phone system and already have meetings and chat
- UCaaS: You want one vendor for calling, meetings and chat
- Your numbers
- Hosted PBX: Keep them
- UCaaS: Keep them
Where Zoom and Microsoft Teams fit
If your business already pays for Zoom or Microsoft Teams for meetings and chat, buying a second meetings and chat tool inside a UCaaS bundle can mean paying twice for the same thing.
The alternative is a hosted phone system that works alongside the tools you already use. 5x5 business VoIP works with Zoom and Microsoft Teams, and staff can click any number in Outlook to place a call.
Which one fits your business?
A hosted PBX fits if
- You already use Zoom or Teams for meetings and chat
- You want to retire an aging phone system without adding new tools
- Your main need is dependable calling, menus and voicemail
- You want phones and internet supported by one provider
Full UCaaS fits if
- You have no meetings or chat tool yet
- You want calling, meetings and chat from a single vendor
- You are ready to move every user onto one new platform
- You want one app for everything, even if it replaces tools staff know
If you own a phone system that still works well, there is a third option: SIP trunking connects it to a voice provider over your internet connection, so you can move to the cloud later on your own schedule.
What to check before you choose
- Your internet connection: every cloud phone system runs over it, so call quality depends on it.
- Your numbers: you keep your existing business numbers, and 5x5 helps you port them.
- Remote and mobile staff: calls should follow people to the softphone app with the same number and extension.
- Special lines: 5x5 replaces aging copper lines for alarm panels, elevators and fax machines with modern service that keeps those devices working.
- 911 rules: FCC rules for multi-line phone systems require direct 911 dialing without a prefix, a notification when someone calls 911, and a dispatchable location sent with the call.
How 5x5 Telecom can help
5x5 Telecom provides a hosted business phone system with enterprise calling features at a flat, low monthly rate. It works with Zoom and Microsoft Teams, so you can keep the meetings and chat tools you already use. Staff can take calls at another location or on the softphone app, and simultaneous ringing can send office calls to a desk phone and mobile at the same time.
When 5x5 also provides your internet connection, calls and the network they run on are supported by one team. Our 24/7 US-based support team answers every ticket within 60 minutes.