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.
The SIP-T48S IP Phone is a dynamic business communications solution for executives and professionals. This phone offers a large touch screen that makes switching between pages and applications swift, easy and convenient. The SIP-T48S is also with Yealink’s Optima HD Voice technology and wideband codec of Opus for unparalleled audio clarity. Business phone users will think they are sitting in the same room with one another. The phone uses Gigabit Ethernet technology for rapid call handling. Plus, it works in conjunction with Bluetooth USB Dongle and WiFi USB Dongle.

Communication on the IP network is perceived as less reliable in contrast to the circuit-switched public telephone network because it does not provide a network-based mechanism to ensure that data packets are not lost, and are delivered in sequential order. It is a best-effort network without fundamental Quality of Service (QoS) guarantees. Voice, and all other data, travels in packets over IP networks with fixed maximum capacity. This system may be more prone to data loss in the presence of congestion[a] than traditional circuit switched systems; a circuit switched system of insufficient capacity will refuse new connections while carrying the remainder without impairment, while the quality of real-time data such as telephone conversations on packet-switched networks degrades dramatically.[16] Therefore, VoIP implementations may face problems with latency, packet loss, and jitter.[16][17]
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.  

Designed for busy executives and professionals, Yealink SIP-T52S is an easy-to-use Media IP Phone with a 2.8-inch color-screen and a distinctive appearance and structure. For its simplified and user-friendly design as well as user interface, it brings the IP phone and users closer to an unparalleled operating experience. With Yealink Optima HD voice technology, T52S enhances its audio quality, adding Opus audio codec delivering superb audio and voice communications.

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.
The advanced Yealink EXP20 is an ideal IP phone system for receptionists, administrative assistants or contact center workers who need to monitor and manage a large volume of calls on a regular basis. The Yealink EXP20 is flexible, powerful and contains a large user-friendly liquid crystal display (LCD) interface that measures 160×320 pixels. As well as contains 20 physical, dual-color LED keys. The additional screen space and added number of buttons simplifies user navigation and streamlines essential operational. Up to six EXP20 phone systems can be strung together on a single daisy chain.
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]

For instance, while AT&T offers landlines with unlimited phone calls for $33.99/month, with RingCentral you can get the Essentials plan, which includes unlimited phone calls starting at just $19.99 per person per month, and you can also enjoy a more extensive list of features. On Grasshopper, the introductory plan costs as little as $26/month, but that includes 3 extensions. With residential VoIP, you have a bundle of features you couldn't find with traditional landlines. Also, because of technology's continual advancements, the features continue to improve every year without a sharp rise in costs. VoIP for home use makes sense because you derive so much more value than what the traditional phone companies of today are offering.

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.

While home VoIP systems are fairly straightforward to set up and use, a VoIP system for all but the smallest of businesses can be quite complex, In addition to have multiple users, business VoIP systems have complex feature sets that are necessary to conduct business in today's world. In addition, a business VoIP implementation must take into account the existence of the data network, even though in most cases it won't share the same infrastructure. This will mean switches and routers optimized for voice traffic, and security that's suitable for both business and VoIP.
The caveat there is the proverbial fine print, usually located just below the really attractive dollar figure. This small print generally details exactly how many months that nice number will remain in effect before the bloom comes off the rose and you start getting billed a much higher number that represents the service's actual cost. Many providers don't even print this higher number on their websites, so be sure to ask the sales guy on the phone before you sign up. The nice number that pulled you in can often double or more once the introductory period wears off. Some providers even attach a minimum length of time that you'll need to suffer these higher costs before you can change or modify the service without getting hit with an additional early-termination penalty fee.
In the European Union, the treatment of VoIP service providers is a decision for each national telecommunications regulator, which must use competition law to define relevant national markets and then determine whether any service provider on those national markets has "significant market power" (and so should be subject to certain obligations). A general distinction is usually made between VoIP services that function over managed networks (via broadband connections) and VoIP services that function over unmanaged networks (essentially, the Internet).[citation needed]
SIP is built to work on a peer-to-peer (meaning endpoint to endpoint) basis. Those two points are called the "user-agent client" and the "user-agent server." Remember that those points can be swapped, so that in SIP, the endpoint making the call is the user-agent client initiating the traffic and endpoint receiving the call is the user-agent server receiving the call.
E911 (Enhanced 911) is a little different to traditional 911 services and is something that you should be aware of. With E911 you need to provide your home address, and this information gets passed to the emergency services if you dial 911. The concerns are that if you have a power outage or an Internet outage then you will not be able to dial 911. If you have a cell phone then you can dial 911 from your device. If you are ONLY reliant on VoIP for your phone service you should be aware of this situation.