Australia's Preferred SIP Trunk Provider

The reliable, cost effective solution for your business telecommunications
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SIP Trunking and your business

Aatrox Communications SIP trunks are a great addition to your company’s unified communications strategy, and are configured and tested to work with 3CX IP PBX, as well as other popular PBX systems.

By specialising in providing flexible and reliable VoIP services to partners and end users, we have differentiated ourselves by being able to advise how to implement the solution from the ground up.

Get in touch with us today to set up your end-customer or SIP partner account.

SIP phone

What is SIP Trunking?

SIP, an acronym for session initiation protocol is a signalling protocol, responsible for initiating, maintaining and ending multimedia sessions. Think of it as a digital phone line – where instead of the traditional PSTN (public switched telephone networklines, you are making calls over the internet. 

SIP trunk rerouting

Simple Rerouting

A SIP phone number isn’t attached to any physical location, therefore allows for simple rerouting to different geographic locations.

SIP channels can be added or removed quickly and easily, making them a very flexible choice for telecommunications.

Cost Effective

Competitive call rates and free calling between remote offices make the change to SIP from traditional telephony a sure way to slash your phone bill.


SIP Trunking allows for the setup of a number of reliability measures including mobile failovers and hosting the SIP trunks across multiple servers.

No Physical Infrastructure

Expanding existing infrastructure no longer needs to be a costly and long process as SIP trunking removes the need for physical phone lines.


SIP Trunking opens up the possibility of fully utilizing the extensive features available in unified communications suites.


Which PBXs are Aatrox Communications SIP Trunks compatible with?

We’ve invested heavily in ensuring our SIP Trunks are compatible with a range of PBXs, and are certified partners with leading IP PBX, 3CX.

Which phones can I use?

You can connect any SIP-compliant physical phone or softphone to an Aatrox Communications’ SIP trunk.

That said, it is far more common to use a PABX such as 3CX.

The telephone requirements are then set by the PABX.

Can I connect an analog PABX with Aatrox Communications' SIP Trunks?

Definitely – and it’s a great way to get some of the benefits of SIP without the expense of replacing your PABX and handsets.

By using a PSTN Gateway (also called a VoIP Gateway) you can connect a SIP Trunk to an analog PABX.

The PSTN Gateway is a physical piece of hardware that essentially converts the digital SIP voice signal into an analog one that is compatible with your existing PABX.

This can directly replace one or more IDSN2, ISDN10 or ISDN30 connections, and immediately provides significant cost savings.

Can I use Aatrox Communications trunks outside of Australia?

Yes, absolutely.

You can register and use Aatrox Communications’ SIP Trunks from anywhere in the world (some anti-hacking restrictions apply but can be lifted on your account by request).

We have customers in the US, the UK, Europe, New Zealand, India, South East Asia, and the Pacific Islands, all using Aatrox Communications’ SIP Trunks to make and receive calls as though they were in Australia.

This saves money, and gives them additional flexibility.

Will my softphone work (e.g Xlite)?

Yes, any SIP compliant softphone can be registered as an endpoint. 

However as mentioned above, it is far more common to use a PABX such as 3CX. The telephone and softphone requirements are then set by the PABX.

Can I dial 000?

Yes, emergency calls can be made just like on an analog phone line.

However, if your internet connection goes down and you have no redundancy, you will not be able to make any calls (including to 000).

What codecs do Aatrox Communications' SIP trunks support?

  • G.711A (also known as G.711alaw)
  • G.711U (also known as G.711ulaw)
  • G.729
  • G.722
  • G.723
  • G.726-16
  • G.726-32
  • iLBC

Codec selection is performed during call setup as per RFC3265. All calls are transcoded to G.711A for termination on the PSTN.


Learn more about SIP trunking and PBX technologies at our FAQ and Definitions pages

3CX partner
3CX advanced certified
3CX certified engineer

Aatrox Communications is an Australian owned and operated full service SIP trunk provider. We specialise in connecting the traditional telephony network to the internet for small and large businesses.