Telephone Lines

Telephone Lines

Need a Telephone Line (SIP Trunk) ?

A Telephone Online SIP Truck service bridges the gap between an existing traditional PBX system and a move towards a modern virtual PBX service.

Our SIP Trunk service has been designed to allow you to connect your IP-enabled phone system to our Cloud PBX service. You can use then use the SIP Trunk service to receive and make calls at the significantly cheaper VoIP rates.

With a SIP Trunk service, incoming calls to our system will pass on the number that was called, allowing you to still fully customise your call routing based on the number dialled. You can port your existing telephone number/number range in to this service (additional costs apply) or alternatively you can use a number/s from one of our number pools.

Telephone Line Benefits We Offer:

Business Telephone Lines SIP Trunks

Business Telephone Line SIP Trunks is the new age business phone lines. SIP (Session Initiation Protocol) is a means of delivering telephone services over the internet. In common terms, SIP Trunks allow you to make and receive calls over a broadband internet connection. Similar to ISDN services, you can purchase blocks of in dial numbers that can be attached to the SIP trunk number, effectively giving you a range of direct phone numbers that outside callers can contact you on. These are usually allocated to individual PBX extensions so that outside callers can call directly rather than go through the main number and the reception.

Business Telephone Line SIP Trunks require an IP phone to operate and are the ideal replacement for traditional telephony and ISDN services. Recent improvements in Australian Broadband Infrastructure such as NBN Internet, allow access to high quality broadband services mean that businesses can now take advantage of this powerful and highly flexible technology.

Telephone Lines

Need more information?

We also provide small phone system, avaya ring central, signal booster and more. For more information or to arrange a quote, contact our helpful and friendly staff on 1300 131 133 and they will be glad to discuss your requirements and tailor the best solution to meet the needs of your business.

Telephones Online expert team understands telephone inside and out and are committed to helping all business enterprises large and small cut costs whilst still accessing one of the very best virtual phone systems around. 

So contact us today to find our how our SIP Trunk service can be made to work for you!


Clients will benefit from our technical proficiency and emphasis on customer service.

Frequently Asked Questions about Telephone Line (SIP Trunking)

SIP stands for Session Initiation Protocol. It is designed to set up connections between devices such as computers, phones, PBXs, video conferencing units and servers.

A SIP Trunk is a virtual phone line that connects your phone system to the public telephone network. It sends the data over a data network, instead of over an ISDN circuit. SIP Trunks can be used instead of ISDN circuits to carry all of your telephone calls, or in conjunction with an ISDN circuit to provide a resilient telephony solution.

That depends on how many simultaneous calls you expect to take place at one time. Obviously, this will depend on your business. If you’re running a call centre it could be one SIP Trunk per operator. For more typical companies, you’d usually have one SIP Trunk for every 5 or 6 phones.

Chances are it will save you money. Up front, you’ll need to pay for a direct connection to your SIP Trunk provider (to ensure good call quality). You’ll probably also need a SIP-ISDN gateway.

As soon as the service is live you’ll save money on your connectivity (because the data connection will be cheaper than your existing ISDN circuit rental). You’ll also save money on your line rental and on your calls.

So the switch from ISDN30 to SIP usually pays for itself.

SIP Trunks utilise your existing data connection, thereby negating the need to spend money on monthly line rental for ISDN circuits. Calls sent over the Internet are much cheaper than calls sent over traditional telephone infrastructure, thereby saving on your monthly call costs. Because SIP Trunks are provisioned over your existing data connection, provisioning can be done instantly as you do not need to wait for circuits to be installed.

Unlike with ISDNs where you have a maximum of 30 channels per circuit, a SIP trunk is fully scalable so you can have as many or as few as users as you want.

By retaining one of your old ISDN circuits, you can add resilience to your phone system, thereby ensuring that even if one of your connections goes down, your telephones will continue to work at all times.

PSTN (Public Switched Telephone Network) is also often referred to as POTS or Plain Old Telephone System. This is the traditional copper network that’s being gradually phased out with the introduction of NBN. Although still in use by a lot of businesses, PSTN lines are old technology that’s being superseded by IP telephony. As Australia’s broadband infrastructure is rolled out, PSTN lines will be decommissioned and services transferred to digital lines and sip trunks.

PSTN lines don’t require a telephone system and are often used by smaller businesses or as standalone lines for EFTPOS, Fax or delivery of a DSL service.

ISDN (Integrated Services Digital Network) is a form of digital network technology that enables multiple concurrent telephone calls using the one PSTN line. Essentially, this is a form of IP telephony where a special data connection is used to deliver telephone services using the existing copper lines. There are two main ISDN networks in Australia, Optus and Telstra. Although the technology is pretty much the same, there are some differences. The main one being that optus multiline is available in increments of one call lines (ISDN channels) over and above the first ten. Telstra’s ISDN is only available in blocks of ten i.e. ISDN 10, ISDN 20, and ISDN 30.

ISDN lines require a telephone system fitted with a PRI (primary rate interface) card and come with high end features and functions such as extension level billing and multiple direct in dial numbers.

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We Provide the Best Service in Industry​

Our service includes new telephone system installation and relocation of existing phone systems, supply and maintenance of spare parts, Upgrading of current business phone systems and stock a full range of spare phones for all systems.

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