The SIP Phone Guide: What They Are & How They Work

You rely on your business phone system to keep your business running, but what if it could do more than just voice calls? That’s where SIP phones come in. SIP phones use the internet to make and receive calls instead of traditional landlines. They provide tons of advanced features like video calling, call management, and more, helping you improve communication.

If you’re looking to upgrade to a modern phone system, we’ve got you covered. In this guide, we’ll explain everything you need to know about SIP phones, from how they work to top-rated models for businesses of all sizes.

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What Is a SIP Phone?

A SIP phone is a type of business phone that uses the internet to make and receive calls instead of copper wires. SIP, which stands for Session Initial Protocol, is the technology that starts, manages, and ends voice and video calls over IP (internet protocol networks).

Unlike analog desk phones that plug into a wall jack, SIP phones connect to your network using Wi-Fi or a wired connection and communicate with a VoIP or hosted phone system. Calls are routed through the internet, which allows you the flexibility to use SIP phones anywhere you have an internet connection.

SIP phones can be physical desk phones, conference phones, or software-based apps that run on computers and mobile devices. As long as the device supports SIP and has an internet connection, it can function as a phone.

What Is SIP?

SIP, or Session Initiation Protocol, is a communication standard that’s used to start, manage, and end voice, video, and messaging sessions over the internet. It’s the signaling technology behind most modern VoIP systems. While it doesn’t carry the voice itself, it handles the connection so that audio and video can be transmitted smoothly in real time.

SIP works across different devices and platforms, which is why it’s widely used in business phone systems.

Main SIP Phone Features

SIP phones can do much more than analog phones, which is why they’re ideal for modern business communication. Some of the top SIP phone features include:

Conference calling: Communicate with three or more parties in a single call without the need for a separate service.
Team messaging: Send messages to team members throughout the workday.
HD voice quality: High-definition audio delivers clearer calls with less background noise than traditional phones.
Call forwarding: Forward calls to other extensions, mobile devices, or voicemail so you never miss calls.
Caller ID and call history: View incoming caller information and access detailed call logs from the phone’s interface.
Auto-attendants/IVR: An automated menu greets callers and routes them to the right person or department.
Call queues: When call volume is high, calls are placed in a queue so they can be answered in order.
Remote use: Access your phone number from anywhere and keep the same extensions, as long as you have an internet connection.
Call routing: Calls are routed based on predetermined rules like skills, hours, or availability.
Visual voicemail: Voicemails are transcribed so they can be reviewed quickly.
Analytics and reporting: Keep track of call volume, wait time, agent performance, and other key metrics.

VoIP vs SIP

VoIP and SIP are closed related terms, but they are not the same thing. VoIP, or Voice over Internet Protocol, is the broad technology that allows voice calls to be made over the internet rather than traditional phone lines. Any phone system that sends calls over an IP network is considered VoIP.

SIP, on the other hand, is a specific protocol used within VoIP systems that sets up, manages, and ends calls. Essentially, SIP tells VoIP systems how to control communication sessions, but it’s not the only one. Other types of VoIP protocols include H.323, H.248, Real-time Transport Protocol (RTP), Session Description Protocol (SDP), Jingle, Skype protocol, and WebRTC.

Can You Use VoIP with SIP?

Yes, VoIP and SIP are designed to work together. In fact, SIP is used in most VoIP phone systems. It’s simple, broadly compatible across devices and vendors, and flexible, making it the industry standard. SIP handles call setup and control, and VoIP carries the actual voice data once the call is connected. Together, VoIP and SIP provide crystal clear calling with advanced features.

Types of SIP Phones

SIP phones often look just like traditional desk phones, but they work completely differently. You can typically choose from hard phones (physical phones) or softphones (software-based phones).

Hard Phones

Hard SIP phones are physical phones that are built specifically for SIP-based VoIP systems. They connect via Ethernet or Wi-FI and often include HD voice, multiple line support, programmable keys, touchscreens, and/or color displays.

Some types of hard phones include:

Desk phones: These look like traditional desk phones but only work over the internet.
Video phones: Video SIP phones include a web camera that enables video calls from your desk phone.
Cordless phones: Cordless phones use a wireless handset connected to a base station that supports SIP. They are commonly used in warehouses, retail stores, and medical offices.
Conference phones: Designed for meeting rooms, conference SIP phones feature multiple microphones, speakers, and echo cancellation so that several participants in the room can join a single call.

Softphones

Softphones are SIP-enabled applications that run on computers, tablets, or smartphones. They let you make and receive business calls using a headset or built-in microphone without the need to purchase hardware.

To use a softphone, you need to set up a VoIP service with a provider. From there, you can typically log into the app on your phone or computer and start making calls. Softphones allow you to make and take calls from your business number from anywhere, which makes them ideal for remote workers and mobile teams.

What Is A Virtual Phone Number?

How a SIP Phone System Works

SIP phone systems use the internet to place and receive calls, using a mix of SIP signaling with VoIP technology. Instead of relying on traditional phone lines, the system routes calls through an IP network.

SIP phones are connected to the internet by Wi-Fi or Ethernet cable. When you make a call, your SIP phone connects to the VoIP provider’s server. The call goes through two separate paths. The signaling path handles the behind-the-scenes communication while the media path transmits the voice data.

You can set up a SIP phone system in two ways. SIP trunking connects your existing phone system to the internet. If you already have a legacy phone system installed, this can be a good option. If you don’t want to purchase and maintain any equipment, hosted SIP phone systems offer you the same benefits and features without the upkeep. Instead, the VoIP provider manages all the hardware in their data centers and provides service over the internet.

How SIP Calls Work

Although the result is the same–a two-way conversation in real-time–SIP calls and traditional phone calls work differently behind the scenes. Landline phone calls use copper wires to transmit your voice as electrical signals through the Public Switched Telephone Network (PSTN). SIP calls can interact with the PSTN, but the process is different. Here’s a look at how SIP calls work:

You dial a number using your SIP phone, just like you would with any other phone.
The SIP phone sends an invite request that includes details about the caller, the recipient, and how the call should be handled.
The SIP system locates the recipient and determines the best path to connect the call.
Once the recipient accepts the call, the system establishes a session.
When you talk, your voice is converted into digital data packets. The voice data is transmitted over the internet using VoIP, while SIP continues to manage the session.
When the data reaches the recipient, it’s converted back into audio. This happens almost instantly.
If there are any issues with jitter, delay, or packet loss, SIP can adjust settings to improve the audio quality.
When one of you hangs up, SIP sends a Bye request that ends the session.

Benefits of SIP Phones

Looking to modernize your business phone system? SIP phones provide tons of benefits like flexibility, advanced features, and lower communication costs. Here are some of the top benefits of SIP phones:

Lower costs: SIP phones eliminate the need for traditional phone lines, which can help your business save on monthly service fees. Plus, rates for long-distance and international calls are much lower. Some plans even offer free international calls to certain countries.
Scalability: Adding new users or phone numbers is simple when you use a SIP phone system. You can scale up or down as your needs change without installing new wiring or purchasing expensive hardware.
Advanced features: SIP phones come with tons of advanced features that typically aren’t available on analog phones. Common features include call forwarding, voicemail-to-email, auto attendants, call queues, conferencing, and call recording.
Mobility: SIP phones work anywhere, as long as you have an internet connection. This means that employees can access the same business extension and features while working from home or on the go.
High-quality audio: With HD voice support and modern codecs, SIP phones provide crystal clear audio with less latency and background noise than traditional phones.
Business continuity: If your office experiences an outage, calls can be rerouted to mobile devices or alternate locations so that communication continues uninterrupted.
Integration with business tools: SIP phone systems can integrate with CRMs, help desk software, and collaboration tools, helping your team work more productively and provide better customer support.

Top Rated SIP Phones

Whether you’re looking for something basic or more advanced, there are tons of SIP phones to choose from. Here’s a list of some of the top-rated SIP phones:

Basic

Poly Edge E220: With advanced noise canceling, a 2.8” color LCD screen, and up to 4 lines, the Poly Edge E220 is a user-friendly model that costs $160.
Yealink SIP-T54W: This highly-rated model offers both wireless and wired connectivity. It comes with a 4.3” color LCD screen, noise canceling, and a cordless handset. This SIP phone costs $119.

Mid-Range

Yealink SIP-T74W: With a cost of $200, the Yealink SIP-T74W is a robust, mid-range SIP phone. It connects to up to 16 SIP accounts and comes with a 4.3” color display. The SIP-T74W supports both Wi-Fi and Ethernet connections and comes with built-in Bluetooth.
Poly VVX 350: The Poly VVX 350 is a highly-rated SIP phone perfect for high-volume call environments. With noise cancelling and HD voice, calls are crystal clear. The VVX 350 costs $220.

Advanced

Cisco IP Phone 8865: With a cost of $350, the Cisco IP Phone 8865 is a premium phone built for managers and executives. It connects via WiFi or Ethernet, and includes a number of options for headset connectivity. Its 5” touchscreen enables video calls, while its robust security features protect your communications.
Yealink SIP-T77U: The Yealink SIP-T77U is built for executives and managers. With a large color screen and ultra-slim body, the phone is both attractive and highly functional. It comes with 3W speakers for audio enhancement, accessibility mode, night/day modes, and an intuitive UI. This SIP phone costs $349.

How to Choose a SIP Phone Service Provider

Choosing the right SIP phone service provider is one of the most important decisions you can make when upgrading to VoIP. A good provider ensures your calls are crystal clear and pricing is transparent. Here are some tips to keep in mind before you make any final decisions:

Does the provider have a proven track record of strong network performance and uptime? Many reputable SIP providers offer uptime guarantees of 99.9% or higher, meaning service stays online almost all the time.
Avoid surprises by choosing a provider with clear pricing and no hidden fees. Make sure you understand pricing, setup fees, add-on fees, and any other costs before you sign anything.
Can you scale your SIP phone system as your needs grow? A good SIP provider lets you easily add or remove lines and services as your team expands.
Look for providers that offer strong security features like encryption for calls and control channels, fraud detection, and compliance with relevant regulations, such as HIPAA and GDPR.
Even the best systems can have technical issues every once in a while. Choose a provider that offers responsive, reliable support and multiple ways to reach them. Reviews from other customers can help you gauge how well a provider supports its users in real situations.
Enlist the experts at Thor Technologies for more help. Whether you’re an SMB or an enterprise, we work with you to understand what your business needs in a SIP phone system. We research multiple providers, providing neutral recommendations based on your needs and budget.

If you’re ready to upgrade to SIP phones, give Thor Technologies a call today. With our expert help, you can make confident tech buying decisions that will help your company grow.

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