VoIP is a relatively new technology and it has already achieved wide acceptance and use. There is still a lot to improve and it is expected to have major technological advances in VoIP in the future. It has so far proved to be a good candidate for replacing the POTS (Plain Old Telephone System). It, of course, has drawbacks along with the numerous advantages it brings; and its increasing use worldwide is creating new considerations surrounding its regulations and security.
VoIP has drastically reduced the cost of communication by sharing network infrastructure between data and voice.[48][49] A single broad-band connection has the ability to transmit more than one telephone call. Secure calls using standardized protocols, such as Secure Real-time Transport Protocol, as most of the facilities of creating a secure telephone connection over traditional phone lines, such as digitizing and digital transmission, are already in place with VoIP. It is necessary only to encrypt and authenticate the existing data stream. Automated software, such as a virtual PBX, may eliminate the need of personnel to greet and switch incoming calls.
The following table provides a high level summary of how residential VoIP service compares to other alternative solutions for home phone service. The table compares this service to a regular landline, a bundled phone service from a cable company such as double or triple play, and a cell phone service. The cell phone is included as some people decide to just get rid of their wired phone and use their cell phone for all calls. Free services such as Skype are not included as they are not effective, like for like, landline replacements in our opinion.

While there are still a few other legacy protocols around, and a few non-SIP standards, such as H.232, SIP is what's used for the vast majority of modern VoIP phone systems. The most common use I've seen for H.232 has been in dedicated video conferencing systems. SIP, meanwhile, handles phone service, video conferencing, and several other tasks just fine, which is why its use is so widespread. Where it has trouble is with data security, but more on that in a bit.  
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).
Similar to its popular small business VoIP solution, Ooma Office, the company touts its on-premises VoIP appliance to power its residential service. You'll find three versions of this device to choose from: the Ooma Telo, Ooma Telo Air or Ooma Telo 4G, but they all sit between your Internet router and your phones, making installation of this low-cost service plug-and-play.  
There are some solutions to this issue if you have concerns. The most obvious is to utilize Uninterruptable Power Supplies (UPS) for those short outages, or a generator if you live somewhere where outages are more common (and for your fridge!). With so many people having cell phones these days most people will not be too concerned with this issue, especially when they consider the money they are saving. Most services include a call forwarding feature so you can always set that up to go to your cell phone so you do not miss important calls.
E.164 is a global FGFnumbering standard for both the PSTN and PLMN. Most VoIP implementations support E.164 to allow calls to be routed to and from VoIP subscribers and the PSTN/PLMN.[27] VoIP implementations can also allow other identification techniques to be used. For example, Skype allows subscribers to choose "Skype names"[28] (usernames) whereas SIP implementations can use URIs[29] similar to email addresses. Often VoIP implementations employ methods of translating non-E.164 identifiers to E.164 numbers and vice versa, such as the Skype-In service provided by Skype[30] and the ENUM service in IMS and SIP.[31]
SIP networks usually have a proxy server and a SIP gateway. The proxy sever helps lighten the functional requirements of SIP endpoints. It also acts as both client and server, but it adds functionality around call routing and policy-based management. SIP gateways handle the routing and connectivity requirements for connecting SIP calls to other networks. Typically, the advanced features of the VoIP vendors we review here are largely based on the proprietary management technology they build into their proxy servers and gateways. By offering VoIP solutions where these elements of a SIP solution are hosted in the cloud, the providers reviewed here have more flexibility in building advanced features since they have more control over deployment and reliability.

Yealink DECT repeater RT30, designed in accordance with Digital Enhanced Cordless Telecommunication (DECT). The repeater can be deployed to extend the DECT radio coverage of Yealink W60B base station significantly in all directions, and when working with W60B, it supports two RT30 cascaded. Clear LED indicators are used to distinguish different DECT statuses. Its elegant design and easy installation are typically suitable to be used in the ambiance of all business environments.
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.   
However, you may also want features like on-hold music, call queues, voicemail to email translation, and automatic answering and forwarding of calls. If all of the employees are working out of the office, you can use the automatic attendant to determine which employee should receive the call. The attendant then can route the call to that employee’s mobile phone.
Fortunately, most of the providers reviewed here have engineering staff that will contact you as part of your setup process to help your IT staffers test and optimize your network prior to deploying their solutions. That's definitely something we recommend, but there are steps you can take now to prep your LAN for VoIP and make the deployment process that much easier.

That situation is for fairly pristine network and business conditions, however. Companies with legacy equipment or unique business needs may need a hybrid PBX, in which a portion of the voice network remains in the analog world, while the rest is converted to cloud-based VoIP. This could happen if you occupy an older building without the necessary Ethernet infrastructure to support VoIP or if you had custom software built a long time ago that simply isn't compatible with newer phone technologies.
The T.38 protocol is designed to compensate for the differences between traditional packet-less communications over analog lines and packet-based transmissions which are the basis for IP communications. The fax machine may be a standard device connected to an analog telephone adapter (ATA), or it may be a software application or dedicated network device operating via an Ethernet interface.[35] Originally, T.38 was designed to use UDP or TCP transmission methods across an IP network. UDP provides near real-time characteristics due to the "no recovery rule" when a UDP packet is lost or an error occurs during transmission.[36]
Be aware, however, that there are significant security implications regarding the use of mobile softphones on employee-owned devices. While it's possible for your employees to simply download the appropriate software from their respective app store, your IT department should be involved with allowing access while also confirming that necessary security steps are taken. Also be aware that there are important reasons not to allow soft phone installations on private devices of any type because you may not be able to remove that phone client if the employee leaves the company, and because local laws may impact how much control you have over the use of the device.
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.
VoIP endpoints usually have to wait for completion of transmission of previous packets before new data may be sent. Although it is possible to preempt (abort) a less important packet in mid-transmission, this is not commonly done, especially on high-speed links where transmission times are short even for maximum-sized packets.[18] An alternative to preemption on slower links, such as dialup and digital subscriber line (DSL), is to reduce the maximum transmission time by reducing the maximum transmission unit. But since every packet must contain protocol headers, this increases relative header overhead on every link traversed.[18]
Most businesses need a portable phone system that can be used anywhere. Of course, landlines do not meet this criterion, and no landline is suitable communication during the journey. The answer is a digital VoIP service that can be used anywhere in the world. All you need is an internet connection and your VoIP phone can be connected to any phone number in the world, whether it is connected to the VoIP network or not.
VoIP has drastically reduced the cost of communication by sharing network infrastructure between data and voice.[48][49] A single broad-band connection has the ability to transmit more than one telephone call. Secure calls using standardized protocols, such as Secure Real-time Transport Protocol, as most of the facilities of creating a secure telephone connection over traditional phone lines, such as digitizing and digital transmission, are already in place with VoIP. It is necessary only to encrypt and authenticate the existing data stream. Automated software, such as a virtual PBX, may eliminate the need of personnel to greet and switch incoming calls.
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]
As always the best place to start is at the beginning! The following buttons provide access to some of our best guides and tools for getting started with VoIP. These articles give a great background into VoIP, help you understand all the basics, and answer most people questions. The VoIP/Speed test tool performs a test of your Internet connection and provides a great indication of how well VoIP will work at your home. We highly recommend running this test.
×