What's the difference between SIP and VoIP?

The IT and telco world is littered with acronyms, and it doesn’t make things easier that many of them seem to stand for the same thing. Two of these acronyms are VoIP and SIP, and they’re often mistaken for each other. Let’s have a look at the differences between the two terms.

What is VoIP?

VoIP (Voice over IP) is a broad term. It’s also called IP telephony, broadband telephony or Internet telephony. Regardless, they all refer to the technology that allows a call to be made over the Internet.

You see, VoIP isn’t part of the public switched telephone network (PSTN). When you call over VoIP, the information is sent as data.

To use VoIP, you need some kind of VoIP phone that can make calls over the Internet. VoIP takes an analogue signal and compresses it to a digital one when you call. This is then sent via the Internet as data. A VoIP call only goes via the Internet or a private, internal network.

Two types of VoIP-phones

A VoIP phone can be used in two ways, but it’s always a call over the Internet, regardless if it’s based on hardware or software. You can use a VoIP phone to call other VoIP phones, fixed phones or mobile phones.

  1. VoIP on a fixed phone.
  2. VoIP on mobile phones or the computer (softphone).

The simplest VoIP phones work about the same way as a regular phone, but they’re connected to your computer wirelessly or directly via USB. That can be a fitting solution for a conference room or your reception.

VoIP can also be used as a software program on your computer or an app on your mobile phone. If you make a call from your computer, the software will create a direct connection (P2P) to the computer you’re calling to. 

What is SIP?

SIP, on the other hand, stands for Session Initiation Protocol. What does it mean? It means that SIP is a communications protocol used for most types of VoIP deployments. That last part is key: SIP is just one protocol out of many that can be used to implement VoIP, much like HTTP is the basis for web pages.

A protocol is a system of digital rules that allows devices to communicate. SIP is the most prevalent protocol and the industry-standard out of these. With a SIP trunk, you can call via the Internet to everyone – regardless if they use VoIP or the PSTN. For SIP-trunking to work, your PBX needs to be SIP-compatible.


SIP-trunk och VoIP – så hänger de ihop 2


VoIP versus SIP – not a direct comparison

As you can see, VoIP and SIP refer to different things. Generally, both VoIP and SIP are about making calls over the Internet instead of using a socket or copper wire. You can say that VoIP is a term for telephony over the Internet, while SIP is a service.

SIP is the “language” that the phones use to communicate, while VoIP is the actual call. You can use VoIP without SIP-trunking, but not SIP-trunking without VoIP.

It’s more accurate to talk about VoIP with and without SIP. Or rather, VoIP versus UCaaS (Unified Communications as a Service). You can read more about UCaaS here.

To summarise: SIP enhances VoIP into a multimedia communications experience, whether it’s through video calls, text or by sending files. Without SIP, it’s a voice-only internet phone service.


What does this mean for your business?

Making online calls is cost-effective. You’ll reduce the total costs for calls since you can call for free via the Internet.

It’s also scalable since you don’t have to deal with wires and specific sockets. Use Ethernet cables and the same wireless network you use for your computers. This will give you flexibility since you won’t rely on the office for making calls – you can work from wherever.


If you stand to choose between VoIP with or without SIP, ask yourself what your communication needs look like.

Are you content with only using voice communication? Go with VoIP without SIP.

However, if you plan on scaling up your business and want to incorporate all the features that come with unified communications – choose VoIP with SIP.

VoIP, SIP or UCaaS – what’s right for you?

It all depends on your communication needs. Are you a smaller company that mostly uses voice calls? Then a simpler VoIP solution that complements your telephony solution will work.

But if you’re growing and know that your communication needs will change, you should look for SIP, or preferably UCaaS solutions. This will result in savings and increased productivity.

Do you want a unified solution for your communication from one supplier? Then it’s a UCaaS-solution you’re looking for.


We hope you’ve learned a thing or two about these two terms. If you need VoIP or a UCaaS-solution that is easy to use, cost-effective and reliable – look no further than Telavox!


See Telavox in action contact sales  <https://telavox.com/contact-us/>