Mass-market VoIP services use existing broadband Internet access, by which subscribers place and receive telephone calls in much the same manner as they would via the public switched telephone network (PSTN). Full-service VoIP phone companies provide inbound and outbound service with direct inbound dialing. Many offer unlimited domestic calling and sometimes international calls for a flat monthly subscription fee. Phone calls between subscribers of the same provider are usually free when flat-fee service is not available.[citation needed]

That covers VoIP basics, but what about the more advanced options, and why is VoIP able to offer more advanced features where a regular phone can/t? Again, the secret is software. A VoIP system, whether home or business, can access a much richer software layer than a standard line from the plain old telephone service (POTS). On the business side, this flexibility has extended to integrating VoIP with other forms of communication to such a degree they all become a single platform, generally called Unified Communications as a Service (UCaaS). You won't anything that sophisticated when you're shopping for residential service, however.

Ooma advertises only two plans: Ooma Office and Ooma Office Pro. Ooma Office includes unlimited domestic calls, three-way calling, virtual fax machines, plus most of the industry-standard features you’d expect from a leading private branch exchange (PBX) provider. Meanwhile, Ooma Office Pro offers more premium features, including call recording and enhanced call blocking—to name a few. But with either plan, you’ll have to pay a $29.95 one-time activation fee to get your service started.
If you're wondering what you get with a softphone that you won't with a standard phone handset, then that depends on the service. Business-class softphones offer all kinds of features related to online meeting collaboration, call routing, multi-line conference calling, and more. From a residential VoIP perspective, you'll most often find video conferencing (though more and more this is becoming a separate product from most providers), a voicemail-to-text converter, detailed call records, and user controls for users other than yourself. Some services also offer faxing, text chat, and call metering so you can see how much you're spending.
VoIP allows both voice and data communications to be run over a single network, which can significantly reduce infrastructure costs. The prices of extensions on VoIP are lower than for PBX and key systems. VoIP switches may run on commodity hardware, such as personal computers. Rather than closed architectures, these devices rely on standard interfaces.[12] VoIP devices have simple, intuitive user interfaces, so users can often make simple system configuration changes. Dual-mode phones enable users to continue their conversations as they move between an outside cellular service and an internal Wi-Fi network, so that it is no longer necessary to carry both a desktop phone and a cell phone. Maintenance becomes simpler as there are fewer devices to oversee.[12]
Voicemail routing can take multiple forms, but they're basically rules you can apply to incoming calls that will automatically route them to voicemail without even causing a ring. For example, if calls come in with Caller ID blocked, those can be routed directly to voicemail. Or if you're simply not into talking to anyone, you can hang out a digital Do Not Disturb sign and route all calls to voicemail, perhaps until you're feeling more social or every day between the hours of 9 PM and 7 AM. 

IP communication provides for device mobility. For example, a residential broadband connection may be used as a link to a virtual private network of a corporate entity, in which case the IP address being used for customer communications may belong to the enterprise, not being the IP address of the residential ISP. Such off-premises extensions may appear as part of an upstream IP PBX. On mobile devices, e.g., a 3G handset or USB wireless broadband adapter, the IP address has no relationship with any physical location known to the telephony service provider, since a mobile user could be anywhere in a region with network coverage, even roaming via another cellular company.

We recognize that not all our readers’ businesses are based in the US. So we took another pass at our content to provide more information on each provider’s international offerings. And because 8x8’s international rates on calls made from the US are so good, we bumped it up to our number five spot. Finally, we added info about Ooma’s new plan (Ooma Office Pro) to the offerings mentioned below.


The most widely speech coding standards in VoIP are based on the linear predictive coding (LPC) and modified discrete cosine transform (MDCT) compression methods. Popular codecs include the MDCT-based AAC-LD (used in FaceTime), the LPC/MDCT-based Opus (used in WhatsApp), the LPC-based SILK (used in Skype), μ-law and A-law versions of G.711, G.722, and an open source voice codec known as iLBC, a codec that uses only 8 kbit/s each way called G.729.


Operators of "Interconnected" VoIP (fully connected to the PSTN) are mandated to provide Enhanced 911 service without special request, provide for customer location updates, clearly disclose any limitations on their E-911 functionality to their consumers, obtain affirmative acknowledgements of these disclosures from all consumers,[65] and 'may not allow their customers to “opt-out” of 911 service.'[66] VoIP operators also receive the benefit of certain US telecommunications regulations, including an entitlement to interconnection and exchange of traffic with incumbent local exchange carriers via wholesale carriers. Providers of "nomadic" VoIP service—those who are unable to determine the location of their users—are exempt from state telecommunications regulation.[67]
Now that so many people are working from home, keeping your business' voice communications organized and centralized can be tricky. Fortunately, that's where cloud-served voice over IP (VoIP) providers can shine. With cloud VoIP (sometimes called a cloud PBX system), you can move direct extensions to new geographical locations simply by clicking a mouse. Devices can also change with similar ease either with a software download or simply by re-configuring call forwarding. With many of these systems also adding a wide variety of team collaboration features, cloud VoIP is probably the best COVID-19 investment a business can make.
That being said, Grasshopper doesn’t offer any conferencing tools. For that, you’ll have to sign up for join.me—Grasshopper’s sister company. This service offers both video and audioconferencing, but it does cost an extra $10–$30 per month. That’s another strike against Grasshopper, since most providers in Grasshopper’s price range include conferencing features.
All 8×8 plans include team messaging, HD videoconferencing, and screen sharing, you you can easily keep all your at-home team members engaged and collaborative. And contact centers that have transitioned to remote work can still enjoy features like omnichannel routing, which allows your employees to engage with customers via chat, social media, text, and phone—all in one platform.

Few things in life are set in stone, and the same should be true of your VoIP plan. It’s wise to find a plan that is scalable and which you can easily expand if need be. You’ll want to know if you can break your contract early if you find a better deal elsewhere, or if you can easily switch plans with the same company in order to take advantage of more features, or to get rid of some you don’t need. 
Editors' note: Line2 is owned by J2 Global, the parent company of PCMag's publisher, Ziff Media Group. If you have questions you need answered about business VoIP, then remember to subscribe to PCMag's Small Business Newsletter and join the [email protected] business community on LinkedIn, and you can ask vendors, other professionals like yourself, and PCMag's editors.   
Some form of call center capability is often available, though many times either as a different product version or simply a higher pricing tier, so be careful before you assume you'll be getting those features. These capabilities are meant to support large sales or service desk staff and their need to route and process a relatively large number of incoming customer or user calls. That means complex menu trees, an auto-attendant for routing, and service queues. You'll probably find you need interactive voice response (IVR) capabilities, and that should be backed up by support for a live operator or some other type of human intervention.
What makes SIP so popular is not only that it's deep and flexible, but also because it was purpose-built to engage in multimedia (meaning not just audio but also video and even text) communications over TCP/IP networks. For VoIP calls, SIP can set up calls using a number of IP-related protocols, including the Stream Control Transmission Protocol (SCTP), the Transmission Control Protocol (TCP), and the User Datagram Protocol (UDP), among others. But it can also handle other functions, including session setup (initiating a call at the target endpoint—the phone you're calling), presence management (giving an indicator of whether a user is "available," "away," etc.), location management (target registration), call monitoring, and more. Despite all that capability, SIP is simple compared to other VoIP protocols primarily because it's text-based and built on a simple request/response model that's similar in many ways to both HTTP and SMTP. Yet, it's still capable of handling the most complex operations of business-grade PBXes.  

That being said, Grasshopper doesn’t offer any conferencing tools. For that, you’ll have to sign up for join.me—Grasshopper’s sister company. This service offers both video and audioconferencing, but it does cost an extra $10–$30 per month. That’s another strike against Grasshopper, since most providers in Grasshopper’s price range include conferencing features.


Voice over Internet Protocol (VoIP), also called IP telephony, is a method and group of technologies for the delivery of voice communications and multimedia sessions over Internet Protocol (IP) networks, such as the Internet. The terms Internet telephony, broadband telephony, and broadband phone service specifically refer to the provisioning of communications services (voice, fax, SMS, voice-messaging) over the public Internet, rather than via the public switched telephone network (PSTN), also known as plain old telephone service (POTS).
With integration being at the heart of VoIP and UCaaS, you can't make a purchasing decision here without thinking about the future. On one side, think about what you'll need in 1-5 years. On the other side, consider each vendor carefully to see what they've done over the last half decade in terms of product development and keeping up with VoIP and UCaaS trends.
Therefore, VoIP solutions also need to handle MNP when routing a voice call. In countries without a central database, like the UK, it might be necessary to query the GSM network about which home network a mobile phone number belongs to. As the popularity of VoIP increases in the enterprise markets because of least cost routing options, it needs to provide a certain level of reliability when handling calls.

Network routers on high volume traffic links may introduce latency that exceeds permissible thresholds for VoIP. Excessive load on a link can cause congestion and associated queueing delays and packet loss. This signals a transport protocol like TCP to reduce its transmission rate to alleviate the congestion. But VoIP usually uses UDP not TCP because recovering from congestion through retransmission usually entails too much latency.[16] So QoS mechanisms can avoid the undesirable loss of VoIP packets by immediately transmitting them ahead of any queued bulk traffic on the same link, even when the link is congested by bulk traffic.

Unless you’re running a major business out of your house, chances are you won’t need or be interested in the ability to do video conferencing with dozens of people at the same time. The same goes for an auto attendant and business software integrations. First decide which features are priorities for you (unlimited calling, voicemail-to-email, international calling plans, etc.) and then take a look at what each company offers. After all, there’s no sense in paying for features that you don’t need. 

The products and services in this review roundup are focused on business use and because of this either provide some PBX features or serve as full-on virtual PBXes. This may mean, among other things, that they provide service to telephone sets on your employees' desks. Most also support electronic faxing in some fashion, either directly (which can be a significant challenge for some VoIP services) or by simply integrating an incoming fax with your email system. Other popular features are video conferencing and shared meeting software (so meeting attendees not only hear each other but can present presentations or documents in a shared work space).


The interest that VoIP technology is generating for consumers and businesses alike, is creating a high level of demand that is being addressed by more and more providers entering the market. Choosing the best home phone service can now be a challenge as it can be difficult to compare providers that have different pricing structures, different features and different contract terms. Many residential providers names are becoming familiar in the home, such as Vonage, MagicJack and Ooma. Vonage, one of the more expensive options today, is popular due to its unlimited international calling feature. Evaluating Vonage competitors can save you even more money depending on your exact needs.
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