What is SIP? And how does it differ from VoIP?

What is a SIP and how does it differ from VoIP?

The world of telecommunications is one with many abbreviations. GSM, WiFi, VoIP, ISDN or ADSL to name but a few. They are widely used but not everyone knows what is behind these terms.

As we have explained in previous articles, VoIP stands for Voice over Internet Protocol. It is a technology in which voice is converted by the phone into digital packets allowing it to be transported over the Internet.

SIP is a part of this voice technology.

SIP from SIP trunk

SIP is the abbreviation for 'Session Initiation Protocol'. As with VoIP, 'protocol' stands for a set of defined rules that the structure of an established session (between SIP devices) must comply with.

Freely translated, SIP can be said to be the rules that determine how a call is established over the Internet, how packets are created and sent, and how that call is terminated.

This SIP Internet protocol is part of how a PBX communicates with devices and how it sets up and maintains connections.

Here, the SIP Trunk is the connection piece between the PBX and the public telephony network. SIP trunks are digital phone lines, with a company's phone numbers attached to them.

If you choose to run communication via VoIP, you can do so with a phone system in the cloud or with a telephone exchange at your own location or data centre that connects to the telephony network via a SIP trunk.

What is the difference with VoIP?

VoIP is actually a collective name for technologies that allow you to communicate with another user over the Internet. In this regard, SIP is one of the technologies used. The majority of VoIP applications are based on SIP.

Often, the two terms are used interchangeably and one provider will want to sell you a SIP phone, while another will talk about a VoIP device.

Frequently asked questions:

What is SIP?

SIP stands for Session Initiation Protocol. It is a protocol used in telephony to set up a telephone call (session). This occurs when two devices such as two telephones want to establish a connection. Or when two users call each other using softphones such as those of Skype or Apple FaceTime.

What is a SIP device ?

A SIP device refers to a telephone that connects over the Internet to an online PBX. Another term for SIP device is a VoIP device. A SIP device can also be a softphone or an intercom that is connected to SIP and talks to another SIP device.

What is a SIP registration ?

A SIP registration means that a SIP device has registered with an online PBX. The login completes the SIP registration.

What is a SIP address ?

A SIP address is an IP address at which a SIP device can be reached via a data connection. Thus, any SIP device is approachable.

What is a SIP trunk ?

A SIP trunk is a digital voice connection between a (local) SIP PBX and a telephony provider that connects to the public telephone network. To give a PBX phone lines to the telephone network, a SIP trunk is needed with a certain capacity of phone lines. This capacity determines how many simultaneous phone calls are possible at any one time. A SIP trunk is the new modern way of an ISDN telephone line.

Is the SIP protocol the same as VoIP telephony ?

The SIP protocol is 1 part of all the protocols and competing technologies that exist within VoIP telephony to establish digital phone calls.

As an entrepreneur, do I always need a SIP trunk or SIP device ?

If you want a business phone number and want to receive phone calls, we can directly
forward calls to your current mobile phone or other devices. You will then not need (new) SIP devices or SIP trunk.

How do I know if my phone system talks SIP ?

If your current phone system is connected via traditional telephony, you can sometimes still buy a SIP extension to make your phone system suitable for new SIP telephony. It is often cheaper and easier to subscribe to a new online phone system and get rid of the old equipment.

I make a lot of international calls, I would like a SIP trunk so that we can have our devices make international calls at a lower rate over our internet connection.

Let us know how much call traffic you have to which international countries and we may be able to help you get a good SIP trunk to these destinations so you can make cheaper SIP calls.