Finding software can be overwhelming. Software Advice helps businesses choose the right IP PBX software so they can save money with SIP trunking and get the phone system features they need.

Showing 1-20 of 99 products

Nextiva Office

Nextiva's Business VoIP solutions offer small businesses enterprise-level telephony service that helps them to streamline company's communications and establish an in-house VoIP phone system. It offers an integrated and scalable PBX... Read more

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Recent recommendations: 53 recommendations

Platforms: MacWinLinux
Deployments: Cloud, On premise
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Jive Voice

Jive is a great fit for companies needing all the features of a full-fledged PBX system, but doesn't have the upfront costs of a large equipment purchase. Their scalable cloud-hosted PBX stays secure and updated automatically. Read more

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Recent recommendations: 46 recommendations

Platforms: MacWinLinux
Deployments: Cloud, On premise
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RingCentral Office

RingCentral Office takes all the functionality of an enterprise-class PBX phone system and virtualizes it in the cloud. Their all-inclusive system arrives pre-configured to the customer's exact needs, ready to plug in and go. Read more

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Recent recommendations: 45 recommendations

Platforms: MacWinLinux
Deployments: Cloud, On premise
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Vonage Business Solutions

Vonage Business Solutions is a cloud-based communications solution suitable for small and midsize companies. The solution offers a business phone system that enables businesses to connect their VoIP phone system to internet-enabled... Read more

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Recent recommendations: 41 recommendations

Platforms: MacWinLinux
Deployments: Cloud, On premise
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Virtual Office by 8x8

Virtual Office is a collection of comprehensive web-based business VoIP solutions from offered by 8x8. Enterprise grade phone service, virtual meetings, mobile applications, virtual contact centers and more are available to help companies... Read more

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Recent recommendations: 32 recommendations

Platforms: MacWinLinux
Deployments: Cloud, On premise
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Business Voice

Business Voice is a cloud-based VoiP solution created by PanTerra, which allows users to take or make calls from their office phone number, communicate with their team, and have file access, all from any device with an internet connection,... Read more

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Recent recommendations: 24 recommendations

Platforms: MacWinLinux
Deployments: Cloud, On premise
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Ooma Office

Ooma Office is a cloud-based VoIP solution that caters to small businesses across various industry verticals that helps them to manage their business operations. Ooma Office offers various capabilities offered by traditional IP PBX... Read more

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Recent recommendations: 10 recommendations

Platforms: MacWinLinux
Deployments: Cloud, On premise
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Dialpad

Designed for organizations of any size, Dialpad Talk is a cloud-based communications platform that allows businesses to access voice, messaging, meetings and video from any computer, smartphone, or tablet. Other key features include... Read more

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Recent recommendations: 6 recommendations

Platforms: MacWinLinux
Deployments: Cloud, On premise
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Intulse

Intulse is a cloud-based VoIP solution for small and midsize businesses. Key features include conference calls, call transfers, custom hold music, interactive voice response, ring groups, call queues, caller identification and missed... Read more

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Recent recommendations: 5 recommendations

Platforms: MacWinLinux
Deployments: Cloud, On premise
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Twilio Voice API

Twilio's Voice API is a fully programmable VoIP system that helps companies make, manage and route calls to a browser, app, phone and more. Key features include call monitoring, call transcripts, call routing, PBX, auto dialer / predictive... Read more

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Recent recommendations: 4 recommendations

Platforms: MacWinLinux
Deployments: Cloud, On premise
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NICE inContact Hosted Call Center

NICE inContact is a SaaS-based call center software that helps businesses to maximizes the quality of leads and minimizes the cost of client interaction. The solution comprises of many features required to process inbound support requests... Read more

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Recent recommendations: 3 recommendations

Platforms: MacWinLinux
Deployments: Cloud, On premise
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FluentStream VoIP

FluentStream is a business phone solution designed for companies of all sizes. It offers call monitoring, telemarketing, IVR and reporting features within an integrated suite. The solution is available both in cloud-based and on-premise... Read more

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Recent recommendations: 2 recommendations

Platforms: MacWinLinux
Deployments: Cloud, On premise
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Five9 Cloud Contact Center

Five9's Cloud Contact Center brings custom call center PBX infrastructure without most of the expensive equipment. IVR, Predictive Dialing and full CTI make Virtual Contact Center a great fit for call centers of any size. Read more

Platforms: MacWinLinux
Deployments: Cloud, On premise
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Versature

Versature’s cloud-based business VoIP services provide Canadian companies with unified communications and call analytics solutions to help manage their business operations. Versature’s key features include auto attendants, click-to-dial,... Read more

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Platforms: MacWinLinux
Deployments: Cloud, On premise
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net2phone

net2phone’s cloud PBX VoIP phone solution enables businesses to communicate in a variety of methods, whether voice, texting, messaging or web chat, over an array of devices, in the office and on the go. The net2phone solution features... Read more

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Platforms: MacWinLinux
Deployments: Cloud, On premise
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Skype for Business

Skype for Business is a hybrid voice messaging solution that enables teams and individuals across the world to communicate and collaborate. It offers both cloud-based and on-premise solutions. This solution allows users to interact... Read more

Platforms: MacWinLinux
Deployments: Cloud, On premise
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Mitel

Mitel is a cloud-based VoIP phone system that offers collaboration and conferencing tools to enable information flow within the organization.  The solution enables system administrators to manage user settings, set preferences and... Read more

Platforms: MacWinLinux
Deployments: Cloud, On premise
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UberConference

UberConference by Dialpad is a cloud-based web conferencing solution that helps businesses of all sizes by combining messaging, voice and video. While it enables users to join meetings instantly without using a PIN, UberConference... Read more

Platforms: MacWinLinux
Deployments: Cloud, On premise
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3CX

3CX is a software-based PBX that works with SIP standard-based IP Phones, SIP trunks and VoIP Gateways. Pricing for 3CX is based on the number of simultaneous calls that the system supports. Solutions are tailored to different business... Read more

Platforms: Win
Deployments: On premise
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Aircall

Aircall is a cloud-based phone system designed for teams like customer support or sales teams. Aircall is a software that allows companies to get phone numbers in 30 countries, configure them in seconds and forward calls easily across... Read more

Platforms: MacWinLinux
Deployments: Cloud, On premise
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Buyer's guide


Last Updated: April 16, 2019

The term “PBX,” for private branch exchange, is in most cases simply a synonym for business phone system.

Internet Protocol PBXes, or IP PBXes, are phone systems that connect calls via the internet rather than the traditional phone network.

We’ll explain the core features and benefits of IP PBX systems. We’ll also take a look at some of the key factors that businesses need to consider when investing in a new phone system.

Here's what we'll cover:

  • What Is a PBX and an IP PBX?
  • IP PBX
  • Which Businesses Need Them?
  • Key Considerations

What Is a PBX and an IP PBX?

The term PBX itself is a relic from the early-20th Century, as we explain in our extended definition.

 

Switchboard Operators, public domain image

Broadly speaking, a PBX’s function is to unite all the separate phone extensions that a business uses so they can function together as one system. Specifically, PBXs:

  1. Route incoming calls to whichever extension a caller chooses.
  2. Distribute calls automatically to internal extensions based on pre-set rules.
  3. Connect internal extensions to outside lines when employees place a call.
  4. Connect calls internally between the business’s extensions.

PBXs have been performing these same tasks for decades. As the internet increasingly takes over the function of the traditional phone network, however, the capabilities and features of PBXs have also evolved.

IP PBX

VoIP, or the Voice over Internet Protocol, has brought many changes to all aspects of business telephony—PBXs included. With VoIP, it’s now possible to send calls over an internet connection, as opposed to paying for traditional business phone service.

In order to reap the benefits of VoIP, you need an IP PBX rather than a traditional PBX, as an IP PBX system can connect directly to the internet. Older PBX systems, on the other hand, connect to analog or digital phone lines.

There are devices known as gateways that allow you to use VoIP service with an older PBX system. If you’re replacing your system, however, it makes much more sense to simply invest in an IP PBX.

IP PBXs exist in several very different forms. Although they all perform similar functions, there is no strict definition of the term. An IP PBX can refer to:

Hardware-based on-premise systems Specific on-site hardware devices that look much like typical rack-mounted servers.
Software-based on-premise systems PBX software running on a computer outfitted with phone connections.
Virtualized on-premise systems “Virtual machines” installed on commodity hardware running a virtualization platform such as VMware.
Cloud-based systems Systems hosted by a VoIP provider in the provider’s data center rather than a server on your business’s premises, delivered as a service over your Internet connection.

Which Businesses Need Them?

Traditionally, PBXs were very expensive to purchase and maintain, and they were only used by relatively large businesses. Smaller businesses had alternatives such as Key Systems, which are scaled-down and less automated, but perform similar functions. (With Key Systems, users manually select lines: for example, by pressing "9" for an outside line.)

Now it’s common for businesses with even a few employees to use some sort of IP PBX for their office phone system.

IP PBXs allow incoming calls to be routed and automatically distributed, and allow internal extensions to dial each other and share external lines. They provide the same basic functions as traditional PBXs, and can be useful to businesses of almost any size.

Further, as more businesses seek out the conveniences and cost-savings of VoIP telephony, IP PBXs in one of the forms mentioned above have become an increasingly common choice. Rather than trying to modernize an older PBX so it can work with VoIP calls, it often makes more sense to upgrade the whole system. Upgrading also gives buyers a chance to bring in new features which may have previously been unavailable.

Key Considerations

Hosted or on-premise. This is probably the most critical decision to make. Companies should look at both options. On-premise systems will typically have higher initial costs, and may also require periodic system maintenance. Hosted PBXs will cost less up front, and will be managed by the provider, but have higher recurring costs. The total cost of ownership for all potential systems should be compared.

Call capacity. PBXs can only handle a limited number of concurrent calls and a limited number of total extensions or “registrations.” (Each VoIP phone connected to the IP PBX requires a single registration.) Assess how many total connections you’ll need, count one for each hardphone and softphone you plan to connect, as well as any devices such as FAX machines that may also be connected via your existing phone service provider, and estimate how many calls your employees will be making and receiving simultaneously when you’re at peak call volume.

Unified communications. This term refers to a range of features that involve communicating across platforms and between different mediums. A common example of this is visual voicemail: a feature that automatically transcribes voicemail messages and emails the transcript to the recipient. Many IP PBXs have UC functions included.

Security. VoIP calls have special network requirements and they often don’t work with well with standard office firewalls. To avoid problems, ensure that your existing firewall is compatible with SIP and VoIP traffic. An alternative is to get an IP PBX that includes a built-in firewall, as many do. Many also include VPN gateways to connect with a corporate Virtual Private Network.

Finally, you can use a device known as a Session Border Controller (SBC), which provides additional security specifically for VoIP systems by policing the “pinholes” that you need to open in your firewall for your VoIP calls.

Auto attendant. This is the automated answering system that greets inbound calls, presents pre-recorded information and gives callers a list of extension options from which to choose. Most IP PBXs include auto attendants, but the level of functionality supported by different systems differs. Advanced IVR systems, the voice menus that allow callers to complete actions such as checking account balances over the phone, are generally only found in call center suites.