Unlimited SIP Channels for On Prem PBX Systems

We understand that many business have a sunk cost in their on Prem PBX. It does the job and you would rather stay with the system you have and just get a better ROI. SIP provides cost effective voice rates, especially when compared to legacy ISDN. Your SIP voice channels can be combined with existing data and internet access links. SIP trunks will connect directly to on-premises UC and late model PABX systems. Older PABX's can usually interface using gateways too.

Options for older on-premises systems include:

  • Used an existing embedded IP card
  • Add an IP card
  • Add an ISDN gateway

Alternately an MS Teams Phone System or Cloud Business Phone Hosted PBX can be used to replace the phone system if it's too old.

Unlike ISDN, SIP is extremely scalable, and a cost-effective way to ensure your current infrastructure investment is fully optimised. If you’re not ready to move to Cloud Business Phone you can maintain your existing PBX and use a Next Telecom SIP Gateway to establish, manage and terminate calls to any network globally.

To keep your business running, SIP provides enhanced resilience and in the event of a failure can re-route using alternate, redundant links – including 4G services.

Whether you’re hearing about SIP for the first time, or you’re already planning to transform your business communications, Call Next Telecom to speak to an Australian based professional.

Next Telecom SIP as ISDN replacement.


Married to your phone numbers? Number portability allows you to retain your existing numbers when switching providers.


SIP is a cost-effective way of ensuring your current infrastructure investment is fully optimised; delivering quick returns on your investment.


Order the lines you need now, and scale up (or down) quickly if required. SIP is the solution that grows with your business.


Only pay for the number of lines you need and the calls you make, saving you more.


With SIP you’re always online. Quickly divert your calls to alternative locations to safeguard your business in case of system failure.


24/7 support manned by customer service focused engineers.

Contact an Australian based Cloud Communications expert now

SIP Trunking FAQ

What is SIP Trunking?

SIP Trunking is the delivery of incoming and outgoing phone calls over a data connection using a combination of session initiation protocol (SIP) and real-time transport protocol (RTP). Put simply, it is a dial tone over the Internet.

Can SIP trunks replace ISDN services?

Yes SIP Trunks make the ideal ISDN replacement technology. In most cases they will also lead to cost savings over ISDN services that are being decommissioned.

How many SIP Trunks do I need?

A SIP Trunk consists of a number of SIP lines or channels. Each SIP line can carry one simultaneous call – so a trunk with six lines can be used for up to six concurrent inbound or outbound calls. A general guide is to divide the number of users by 2-5, but that should only be used as a guide and will vary based on how you use telephony.

Is SIP call quality good?

Most business grade internet connections are totally suitable for SIP and a good quality SIP call is better than the best quality analogue call. It is important to choose a provider that uses a Tier-1 network and you should ensure you have enough internet bandwidth to support the expected number of concurrent calls. Voice quality is dependent on bandwidth, and your connection’s latency and jitter.

Can I keep my current phone numbers?

Absolutely. You are able to move your existing phone numbers across to this service.

Is SIP the same thing as VoIP?

Although SIP and VoIP are sometimes used interchangeably, they are not the same thing. The term VoIP stands for Voice over Internet Protocol. It is a broad term that covers any phone call made over the Internet. The term encompasses a group of protocol technologies of which SIP is an example i.e. SIP is one of the specific protocols that enable VoIP.

SIP Trunking Features

  • Save on call costs compared to ISDN or PSTN – PAYG or unlimited call plans.
  • 100 Number DID ranges available.
  • Keep your existing numbers. We can port in ISDN and PSTN phone numbers.
  • NBN ready SIP service available prior to the copper cut off.
  • Use your existing phone system with a IP card or a SIP gateway.
  • No physical limit to the number of channels you can use.
  • Flexibility to meet your business demands – increase or decrease channels when you need to.
  • Connect to the Cloud – enables a seamless and simple upgrade to a full Cloud solution down the track.
  • Easy upgrade to MS Teams Calling.
  • A Private, secure data network carries SIP voice Traffic.
  • Guaranteed call quality and backed up with Service Level Agreements.