Companies are choosing VoIP telephony to use a flexible and scalable communication system for business development. SIP is one of the VoIP protocols. Calls use a method of transmitting voice and other multimedia files over an IP network that is called SIP trunking. This solution improves business and team productivity as the company can have multiple calling channels, enjoy HD quality communications, and easily expand the communications system as the company grows.

What is SIP trunking, and how does it work?

The definitions of SIP telephony and VoIP often go together, but there is a great difference between these technologies. The SIP standard expands the capabilities of VoIP telephony, which is aimed at transmitting voice data over the Internet. Users can not only exchange calls due to SIP but also SMS messages, as well as faxes and videos. And if analog telephony uses PSTN (voice signals are transmitted over telephone wires), then VoIP could be used through a SIP trunk.

Simply put, you can imagine a SIP trunk like some kind of digital telephone wires that connect office phones to a communicator and PBX. Such virtual phone lines allow you to receive and make calls over the Internet, while the conversational partner does not need to have SIP (you can call a simple phone number).

Each SIP trunk supports a SIP channel and their number can be unlimited. Many SIP providers ensure channels on demand. This means that you only pay for the required number of channels. Freezvon recommends contacting Support to draw up a telephony plan depending on the projected volume of incoming and outgoing traffic.

Alternatively, you can use a virtual PBX where you can get up to 100 internal lines. This would expand your agents’ capability to talk to customers at the same time.

The way voice transmits over SIP

Codecs convert audio signals and send files to the recipient of the call for the voice to be transmitted over IP. Two codecs are used for SIP transmission.

  • G.711 is a higher standard because voice data is not compressed, and audio quality remains HD.
  • G.729 compresses speech data to transmit information where the bandwidth is limited.

SIP telephony architecture

The use of SIP trunking does not mean that you need to completely abandon the existing PBX infrastructure. You can use analog phones, but first, modify them. This requires SIP gateways that convert the analog signal to digital.

If the company has not used IP telephony before, then it is worth ordering a virtual PBX for which a gateway is not required.

There’s a manual on how to add a Freezvon SIP trunk for FreePBX or configure Asterisk.

You can work with SIP trunking on:

  • PCs, laptops, and tablets, where the SIP client is installed.
  • IP phone.
  • A mobile phone with a softphone (or you just call forward to a cellular/landline number, but outgoing calls will still require a SIP app).

Why do businesses switch to SIP trunk service?

Companies benefit from using SIP technology to communicate with customers and employees. This telephony model allows you to have a single corporate network even if staff work remotely.

SIP Trunking Benefits:

  • No investment in physical hardware. The company does not need to install telephone lines or set up a server. Communication and software updates for IP PBX are provided by the telephony provider.
  • Low cost of calls, including international ones.
  • The ability to manage calls from anywhere, without being tied to an address.
  • Flexibility and reliability of communication. You can continue to communicate with customers by forwarding calls to mobile phones during power outages.

How to start using SIP telephony?

If you need a SIP trunk, but haven’t connected a virtual PBX yet, order it on Freezvon. We provide IP PBX with a free virtual number for calls. The pricing model will be based on the number of users. At the basic rate ($30 per month) you have 5 lines for simultaneous outgoing calls and 50 internal lines for communication between employees and call forwarding between specialists. The number of SIP accounts and channels can be expanded. Contact Freezvon support to connect a SIP trunk or virtual PBX to enjoy all the benefits of VoIP telephony and SIP trunking.