What is a SIP Client and SIP Phone? A Simple Guide to SIP Phones, Clients, and Features

Telecommunications is the lifeblood of any business and the way we communicate and collaborate has radically transformed over the past decade. Now, leveraging cost-effective technologies can help businesses scale while also unlocking all the capabilities they need.

SIP is an underlying technology behind Internet-based communications. However, when navigating the world of Internet-based telecoms, the variety of SIP terms can be daunting and understandably confusing.

So, let’s break down two often confused terms: SIP client and SIP phone. While they can work together, they are distinct concepts to understand. Learn how they vary to help choose the right option for your business.

What is SIP?

Before we dive into SIP clients and phones, let’s take a step back and look at SIP itself. Session Initiation Protocol (SIP) is a protocol developed to initiate, maintain, and terminate communication sessions via the Internet, which involves voice calls, video calls, instant messaging, or even file transfers.

SIP offers an open standard and is highly flexible, making it a cornerstone protocol of Internet-based communications. SIP is an essential part of many modern communication systems, particularly in Voice over Internet Protocol (VoIP) applications.

Additionally, while SIP is restricted to IP-based communications, other technologies have emerged that allow for the calling of any phone number.

A virtual Private Branch Exchange (PBX) allows SIP calls to be made over the broader Public Switched Telephone Network (PSTN) — meaning a SIP call can reach traditional networks, including mobile devices and landlines.

What is a SIP Client?

A SIP client describes an application or device that uses the SIP protocol to enable communication sessions over the Internet. You can think of a SIP client as a “soft” version of a hardware phone as it’s able to operate entirely as software, earning it the moniker “softphone”.

SIP clients can typically be installed on most devices, such as desktops, laptops, mobile phones, and tablets. Once set up, SIP clients can call on these devices without needing additional specialized hardware.

How SIP Clients Work

SIP clients can initiate a SIP session with another SIP-compatible device, including another client or SIP phone. When you make a call, the SIP client sends a SIP INV message to the recipient, signaling a new session that the recipient can accept or reject.

You may also encounter the term SIP trunking, which is the underlying technology that enables SIP clients to execute the end-user experience.

Softphones is an umbrella term for SIP clients, as they’re a “soft”-ware based phone. These SIP clients come in two major forms, such as:

• Mobile apps enable communication over WiFi or mobile data rather than typical networks, allowing travelers and remote workers to continue using business communication.

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• Desktop apps can be a complete solution for employee communications and typically have all necessary features like voice, video, and text. They’ll need a simple universal headset or earbuds with a mic and speaker.
• Cloud softphones can be mobile or desktop apps that provide services via cloud-based infrastructure rather than on-premise systems. A cloud softphone is often rich with integrations and other features that don’t require upkeep from your IT team.

Key Features of SIP Clients

What features should you expect in a SIP client? The exact features depend on the vendor and platform you adopt, but typical features include the following:

• Multi-device compatibility: SIP clients should have cross-compatibility with major devices and operating systems. Some platforms take this a step further, transferring calls between devices without disruption.
• Voice and video calls: In the past, SIP clients were focused on voice calls, but a modern SIP client should also be able to support video calls. Some vendors may have separate products or add-ons for video support, but it should still be available.
• Integrations: As software, SIP clients can feature robust integrations with other business applications. CRMs, calendars, and email can integrate SIP clients to streamline workflows throughout the business.

What is a SIP Phone?

A SIP phone is a physical hardware device designed specifically to use the SIP protocol to make and receive calls over the internet. Unlike software-based SIP clients, SIP phones are dedicated devices that often look and function like traditional desk phones but rely on the internet rather than a landline.

How SIP Phones Work

SIP phones work similarly to desk phones of the past but have been engineered to work with Internet-based platforms. SIP phones are ideal for employees who are used to working with desk phones as the user experience is almost the same.

SIP phones also use SIP trunking to make calls and can often work with an SIP client to provide the benefits of each. The major difference is that SIP phones are physical hardware for making and receiving calls.

Key Features of SIP Phones

As hardware devices, SIP phones have entirely unique features when compared to SIP clients. This feature set can make them the perfect choice for some businesses, while others may not need them at all. Common features of SIP phones are:

• Call quality: Due to being dedicated and specialized hardware, SIP phones can often exceed the call quality of other options. This increase isn’t because of network performance but simply improved circuitry and speakers.
• Dedicated features: Hardware phones typically include physical buttons for common needs, like hold, mute, or transfer. Other necessary dedicated buttons include checking voicemail and quickly reaching other extensions.
• Not dependent on a device: A SIP phone might work in tandem with a SIP client, but this isn’t usually required. SIP phones can be networked directly to the backend infrastructure instead.

Adopt Acrobits for Cost-Effective and Reliable SIP Calling

SIP clients and SIP phones are two options for Internet-based communications. Clients and phones can work together or independently to replace traditional landlines. However, be aware you’ll need a virtual PBX to reach mobile and landline users — unlocking true business calling.

Acrobits is an industry-leading provider of cloud softphones that allow organizations to build the perfect platform for their needs, complete with their own branding. Our softphones are designed to work with or without SIP phones, giving you everything you need to communicate and collaborate.

Ready to leave legacy landlines behind for more cost-effective and reliable communications? Book a demo today or watch our on-demand demos to see our softphone in action.