PBX Quote
Contact Us
PBX Quote
Contact Us

ISDN 10-20-30

Fully Scalable ISDN Solution

Enquire Now

Telstra ISDN and Optus Multiline

ISDN (Integrated Services Digital Network) is a digital network technology that can carry voice and data services in a digital format over a standard telephone line. It allows for between 10 and 30 concurrent telephone calls at the same time over the one service connection. For businesses that require more than 30 call lines, multiple ISDN connections are grouped together.

ISDN Service Disconnections and Migration to IP Lines

Traditional ISDN lines use the copper network to deliver phone services. In line with the roll-out of NBN and other broadband infrastructure, ISDN is no longer available for new service connections. Commencing September 2019, current services are being gradually disconnected and migrated to IP lines. Business IP lines use SIP (session initiation protocol) to deliver phone lines over the internet.

PBX Compatible

Connect Business VoIP SIP Trunks Directly to an IP Enabled PBX System.

No Lock In Contract

Complete Business Flexibility with No Contract Month-to-Month Plans.

Cheap Call Rates

Save $$$ with our Cheap Call Rates and Low Monthly Access Fees.

ISDN Migration Options

Business VoIP SIP Trunks


Business VoIP and SIP Trunks are the new age business phone lines. If your business has a suitable broadband connection, then you should get connected to the latest technology. Take advantage of enterprise grade features and functions, cheap call rates and low monthly access fees.

Hosted PBX Systems


Hosted PBX is another popular option for businesses that require full PBX functionality with their phone lines. At a fraction of the monthly cost of an ISDN2 service, you can gain access to all the features and functions of an enterprise grade PBX while taking advantage of much cheaper call rates. You can start with a single extension and build the phone system as your business grows.

Enquire Now


What is an ISDN Channel?

ISDN is essentially a form of Business VoIP, where the voice traffic is carried through a broadband connection. Each individual telephone conversation with an outside caller requires an ISDN channel to transmit it to the PSTN (public switched telephone network). In other words, an ISDN channel is a call line that allows for the PBX to connect with the outside world. Multiple ISDN channels are required for equal amount of concurrent telephone calls.

Business ISDN Options

BusinessCom can check what type of ISDN service is available at your business premises. We can also check if you can take advantage of more up to date technology like Business VoIP or Hosted PBX. Please call 1300 000 300 or CLICK HERE.

Reduce Your Telco Costs Even Further 

With the rollout of NBN and other broadband infrastructure, an increasing number of businesses are starting to migrate their phone line services to Business VoIP and SIP Trunks. The VoIP technology is gradually replacing traditional telephone lines like PSTN and ISDN.

SIP Trunks are essentially VoIP phone lines that can have one or multiple channels that determine the number of concurrent phone calls that can be made. Apart from much larger capacity than ISDN, SIP trunks offer a greater level of functionality and flexibility. They're fully portable and not restricted to individual premises, and a lot more cost effective.

The majority of PBX systems installed in recent years are IP compatible. Provided your business is connected to a suitable broadband service, that means you can start using business VoIP without having to upgrade your existing phone system. We can check if your business is VoIP ready.

Check to See If Your Business Can Be Upgraded to NBN Ready Business VoIP

We'll check if your business has the necessary broadband infrastructure to take advantage of Business VoIP SIP Trunks or NBN Ready Business PBX System.

Request VoIP Check

Optus Multiline ISDN 10+ and Telstra ISDN 10/20/30 

Both Optus Multiline and Telstra ISDN 10/20/30 are enterprise grade services of the highest quality and deliver functionality previously reserved for enterprise sized businesses. The key differences between them are:

  • Telstra ISDN 10/20/30 is available almost anywhere there is PSTN infrastructure. Optus Multiline is limited to selected areas with Optus broadband infrastructure.

  • Telstra line rental and additional charges are generally higher than Optus Multiline.

  • Optus Multiline allows for services to be scaled in single line increments above the minimum of 10. Telstra only provides ISDN services in blocks of 10.

ISDN has been a trusted business phone line technology for many years. It has and still is being used by 1,000's of businesses of all sizes. Following are some frequently asked questions. If you require any further information please call 1300 000 300 or make an online enquiry.

Difference Between ISDN and ISDN2

ISDN 10/20/30 is primary rate digital service with a maximum capacity of 30 channels (call lines). ISDN2 is a basic rate service with a maximum capacity of 2 channels. Both services deliver digital phone lines with the main difference being capacity and the required PBX functionality. You will need a PRI (primary rate interface) card for ISDN and a BRI (basic rate interface) card for ISDN2.

Do I Require an Active Telephone Service to Connect ISDN?

No. The only requirement is that the premises has the necessary PSTN wiring and available capacity. In almost all cases ISDN is delivered by using PSTN lines (traditional copper lines) to establish a data link. Your premises must have the required PSTN wiring that's not being used for other purposes. To check ISDN availability at your business premises please call 1300 000 300 or CLICK HERE

Do I Require a PBX System?

Yes. A PBX phone system with a PRI (primary rate interface) card is required. Its important to remember there is a difference between ISDN and ISDN2. In most cases, phone systems that have previously used an ISDN2 service require installation of a PRI card. To find out if your system is compatible please call and speak to one of our Business Consultants on 1300 000 300 or CLICK HERE

Will I Need a Separate Telephone Line for the Fax Machine?

No. Your fax number can be incorporated in the ISDN service as long as your PBX system can be configured to do so. You should consult your PBX maintainer to ensure the fax number can be included in the ISDN number range. If for some reason that's not possible, there is still the option of activating a Virtual Fax Service and still eliminating the need for a separate telephone line.

Can I Retain My Existing Numbers?

Yes. BusinessCom has Local Number Portability (LNP) agreements with all the major carriers. You can consolidate multiple numbers from across a variety of platforms i.e. PSTN, ISDN 2, etc. into the one ISDN service.

Can I Transfer Services From One ISDN Network to Another?

Yes. You can transfer services between networks including all the DIDs (direct in-dial numbers).
When transferring ISDN services from one network to another, a new service is installed and the old one is disconnected. Telstra and Optus operate separate networks which means both may not be available at the same premises. Please call 1300 000 300 or CLICK HERE to check availability.

What are Direct In-Dial Numbers?

Direct in-dial numbers are landline numbers attached to the ISDN service. Apart from the main business numbers, consecutive DIDs can be allocated to individual PBX extensions. That way outside callers can dial the extension directly, eliminating the need to go through reception. Direct in-dial numbers are usually available in blocks of 10 and 100 numbers.

Get In Touch With One of Our Business Consultants

Connect to the Latest Technology

Enquire Now