SIP stands for Session Initiation Protocol and refers to a telephone system network protocol based on TCP/IP that can be used to establish and control the communication connections of multiple subscribers or even a hosted call center.

SIP is often used in Voice over IP telephony to establish the connection of telephone calls. The main features of the Session Initiation Protocol are specified in the document. Because the Session Initiation Protocol is an open standard, the protocol is widely used throughout the world. Almost all IP-based and PBX phone systems have SIP.

IP telephony designates telephone activity through a computer network in which data is transmitted according to the IP standard. IP stands for “Internet protocol” and is a set of standards according to which data must be prepared for transmission on the Internet. IP telephony uses the same transmission channels as normal data transmission on the Internet.

SIP phone service providers also offer the possibility of Unified Communication (UC) and the simple integration of fax solutions through XCAPI.

What is Voice over IP (VoIP)?

VoIP is a communication method of making calls over a broadband connection over the Internet as an alternative to regular calls made over an analog phone using the PSTN.

What is ‘IP’ in VoIP?

It is the standard for Internet Protocol. It gives unique addresses to each computer and other devices connected to the Internet (physical or virtual). This allows data to be sent and received between computers over the Internet, including voice data for phone calls.

What is the difference between VoIP and traditional telephone systems?

The main difference is that they use different networks. Traditional telephone system uses the PSTN, while VoIP uses the Internet.

This is how SIP trunks work.

The acoustic signals are digitized during data transmission and divided into several data packets. These packets have a header that includes, among other things, the sender, the recipient, and the status of the message.

SIP trunks are used to establish a connection. SIP phone service providers assigned SIP trunks aligned with PBX phone systems so that this address can identify the user.

When a user turns on his device, he logs in to this server. There the login is recorded. When another interlocutor accesses the corresponding SIP address, this request is transferred to the respective server where the interlocutor is registered. This transmits the call to the terminal equipment, thus generating the call.

The SIP trunks are not subject to a certain connection in contrast to the conventional telephone number. It is available globally if someone logs in with a computer whose terminal is over the Internet using the SIP address. Using special gateways, connecting Internet telephony with the conventional telephone network is possible. This allows you to make calls with a local telephone number to a VoIP phone or vice versa. A media gateway works, for example, with both ISDN and an analog telephone connection.

Main advantages of VoIP for companies

The benefits of VoIP are many and varied, including support for Hosted Call Center with reduced overall telephony costs. These include:

  • Free internal calls: Voice over IP offers the great advantage of saving a lot of resources. IP telephony uses these already existing resources, and in this way, further costs are avoided. With a cloud telephony solution, you can call anyone in your organization free of charge, including colleagues from different offices and switchboards in different countries. There is no need for expensive equipment or contracts with service providers.


  • Cheaper external calls: Normally, VoIP telephony is considerably more profitable than traditional fixed and mobile telephony. This is because VoIP carries voice data over the Internet. This is in contrast to traditional calls over the PSTN network, which requires a dedicated connection for the entire duration of the call. Therefore, compared to conventional phone systems, a VoIP platform can reduce the cost of calls to external mobile phones and landlines.


  • Less hardware: Since the best SIP solutions are hosted in the cloud, they provide the full range of business telephony features without installing expensive physical telecommunications infrastructure. This saves costs while simplifying and accelerating deployment.


The ease of working with your mobile: With a dedicated application – employees can also access all the telephony features of the cloud telephone system on their mobile device. Each user has a unique local telephone number for landline and mobile, making it easier for colleagues and clients to reach them.