SIP Phone Guide 2024 [What They Are, Types, and Benefits]
By Andrea Viktória Filo
| 30. May 2024 |
Call Center
By A. Viktória FiloAndrea Viktória Filo
| 30 May 2024 |
Call Center
    By A. Viktória FiloAndrea Viktória Filo
    | 30 May 2024
    Call Center

    SIP Phone: What It Is, How It Works & The Role it Plays in VoIP

    A staggering 65% of customers expect an immediate response when contacting a business. If they don’t receive this? Well, you all know how consumers react when businesses disappoint them.

    Naturally, this demand for immediacy can add a lot of pressure to your sales and customer service teams. This pressure only intensifies if they have to manage communications via traditional telephone systems, which are notoriously downtime-prone and can impede customer experience.

    To avoid these challenges, and improve your internal and external communications, it’s better to invest in an internet-enabled SIP phone system. 

    Let’s explore what these phones are and why you should make the switch.

    Key takeaways:

    • “SIP phone” refers to any device capable of making and taking internet-based calls.
    • There are subtle differences between SIP and VoIP, with the former being a particular communications protocol that forms part of the latter.
    • There are compelling benefits of internet-based telephone networks, including greater scalability and cost-efficiency.

    What Is a SIP Phone?

    A SIP phone is an internet-enabled device that facilitates telephone calls. These devices transfer audio, video, and multimedia communications via an IP-based network connection, as opposed to traditional landlines which use dated copper wires.

    What Is “SIP”?

    SIP stands for Session Initiation Protocol. In layman’s terms, it’s a set of rules that facilitate an internet-based telephone call. The protocol is responsible for triggering and terminating a session, as well as supporting the transmission of data packets across a network.

    It works hand-in-hand with VoIP (Voice over Internet Protocol), which we’ll dive into later in this guide.

    Types of SIP Phone

    There are three main categories of SIP phone, each with their own characteristics:

    “Hard” Phones

    Are you a fan of old-school technology? For the traditionalists among you, a hard phone looks similar to a standard desk telephone, and functions similarly to one, too. However, this is where the similarities end. 

    Hard phones are internet-ready and built using components that work alongside your SIP protocol. They do not connect to a traditional public switched telephone network (PSTN).


    Of course, not all of your employees will need (or want) a bulky telephone set on their desk. For those on the move or working from a home office, a softphone is a much better option. 

    These are software-based solutions that can turn any internet-enabled device into a phone. The result? Your team can make internal and external calls from their laptop, tablets, or mobile phones.

    Traditional Phones With an ATA Adapter

    If you’d rather stick with your existing traditional desk phones—as opposed to buying new hard phones—this may be the right solution for you. An Analog Telephone Adapter (ATA) allows you to transform any legacy telephone into an internet-ready device.

    What’s the Difference Between a SIP and IP Phone?

    SIP, IP, VoIP—you’re bound to run into all three of these acronyms in most internet telephony articles. But what’s the difference between them? 

    Seeing as we’ve already provided a SIP phone definition, let’s start with IP phones.

    Voice over Internet Protocol (VoIP, or IP for short) technology converts your voice into digital data packets, transmits them over your network, and then rebuilds them into spoken audio on the receiver’s end. There are no traditional phone lines involved, only an internet connection and your VoIP hardware.

    As we mentioned earlier, most VoIP systems do rely on Session Initiation Protocol to function. But this doesn’t necessarily work both ways. It’s possible to conduct internet-based calls without VoIP through SIP trunking.


    SIP trunking allows you to turn any traditional phone into a SIP phone without needing VoIP technology to support it. This means that, if you want to opt for an internet-based telephony system, you can choose between SIP trunking or VoIP.

    To help you understand some of the subtle differences between SIP and IP phones, check our handy table:

    SIP Phones

    VoIP Phones


    SIP phones can facilitate multimedia communications beyond audio calls, such as instant messaging and video calls.

    VoIP phones typically only support voice calls, although some VoIP-based systems have additional features.


    SIP is a protocol that provides the foundation for VoIP calls.

    VoIP is not strictly a protocol. It transmits data over a network connection in collaboration with an internet protocol. 

    Cost and Setup

    If you use SIP trunking, you’ll likely incur a large initial set-up fee. The more outdated your phone systems, the higher the cost.

    VoIP phone systems are much easier to set up and are more cost-efficient by comparison.

    Still confused? You’re not alone. To avoid any misunderstandings, many organizations now use the terms VoIP, SIP, and IP interchangeably. This is because many internet-based telephone systems hinge on all three technologies/protocols. 

    So, if you see any of these acronyms out in the wild, just assume they refer to any phone call conducted via the internet rather than the PSTN

    Benefits of a VoIP or SIP Phone Service

    Speaking of the PSTN, let’s explore why sticking with legacy phone networks could be damaging for your business. In the following section, we’ll list the compelling advantages of VoIP vs PSTN:

    Cut Installation and Maintenance Costs

    One of the main disadvantages of a traditional PSTN system is its lack of resilience. These outdated networks contain a single point of failure. In other words, if the line drops dead in your neighborhood, there’s no quick fix. 

    More than this, fixing, maintaining, and installing these systems not only takes time but can cost you a pretty penny. This is largely due to the specialist labor required and the higher cost of traditional phone hardware. 

    With a VoIP or SIP phone system, you can easily avoid these eye-watering spendings. It’s free to set up most VoIP systems and there’s minimal hardware maintenance required.

    Easily Onboard and Manage Remote Workers

    On-premises solutions require on-premises workers. This chains your employees to your physical office locations and hinders modern working practices. 

    VoIP solutions, on the other hand, allow your business to make and receive phone calls from anywhere

    This means that you can implement a remote or hybrid working environment. Doing so can be great for sourcing top talent, increasing productivity, and improving employee satisfaction. As you can turn any internet-enabled device into a SIP phone, you can empower employees to conduct phone calls on the go, too.

    Establish Local Presences Around the World

    When calling an international phone number via a PSTN network, time is of the essence. With every minute on the line, you rack up higher charges—charges that are completely preventable in today’s digital age.

    VoIP systems eradicate these costly long-distance call charges by enabling you to set up virtual, international numbers across the globe. With Cloudtalk, for instance, you can access numbers from upwards of 160 locations. 

    Besides reducing your costs, international numbers can:

    • Increase customer trust. Local numbers are less likely to set off alarm bells for your customers. 
    • Build your market reach. Establishing a local presence in different countries will open up a new pool of sales prospects and customers, which will have a welcome impact on your bottom line.

    Scale Operations Quickly and Simply

    It’s incredibly difficult to scale your operations and grow your network when you’re tethered to the PSTN. Why? Because the technology is aging, inflexible, and requires hands-on labor to expand. 

    On the other hand, a VoIP or SIP phone service is highly scalable. You can easily add new users, locations, and features with minimal installation and maintenance required.

    Future-Proof Your Business

    Landlines and PSTN networks are a dying infrastructure. Across the world, countries are beginning to phase out these networks and replace them with digital, IP-based alternatives. For example, the UK is already on track to retire their PSTN network by 2025

    To ensure your organization doesn’t get caught out by similar technological transformations, it’s better to adopt an internet-based telephony system now. 

    Of course, this isn’t the only “future-proofing” VoIP can provide. As we’ve already discussed, these systems can enable you to keep pace with changing customer demands, scale your efforts, and improve team productivity. This will help your business stay competitive and agile in the years to come.

    Upgrade your phone system today

    Boost Business Communications With SIP Phones and VoIP

    We’re in the golden age of technology, so why settle for copper wire infrastructure? 

    Almost half of customers are willing to pay more for better customer service. It only makes sense to adopt technology that will improve your business communications rather than stick with outdated infrastructures that will hinder them.

    SIP phones and VoIP systems free you from the inefficiencies of traditional PSTN networks. They empower you to reach customers and prospects in a cost-effective, productive, and seamless manner. The result? You can turn your conversations into conversions.


    How Do SIP Phones Work?

    SIP phones have a unique address, which the Session Initiation Protocol uses to establish, manage, and terminate an internet-based connection. 

    We refer to this as call signaling, and it’s a requisite for any communication transfer—whether it’s audio, video, or multimedia. Once the protocol connects two or more SIP phones (or endpoints), the data transfer can then occur.

    How Do You Set Up a SIP Phone?

    First, ensure your SIP phone (whether it’s a hard phone, softphone, or adapted phone) or VoIP software is connected to the internet. 

    Next, you’ll need to configure the phone via your VoIP solution. If you’re using CloudTalk, this involves authenticating your devices via the Agents dashboard. In most cases, you will only need to enter the username credentials—your device will then finalize the configuration automatically.

    Can I Keep My Number But Switch to SIP or VoIP?

    Yes! When adopting a new SIP or VoIP system—or switching providers—you can port your number. If you’re with CloudTalk, all it takes is one formal email request, a simple verification, and some work on our end.