Choice of Telstra or Optus ISDN Networks

Telstra and Optus

Largest ISDN Coverage

Cheap Call Rates

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.


BusinessCom offers the choice of Australia's two largest ISDN networks, Optus Multiline and Telstra ISDN. Both deliver between 10 and 30 call lines (ISDN Channels) with a single connection. Multiple connections are used for businesses requiring 30+ channels.

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.

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 Features

  • Cost Effective 10+ Lines
  • Scalable 10 to 30 Lines
  • Scalable in Single increments (Optus Multiline Only)
  • Made for PBX Phone Systems
  • Hunt Groups
  • Enterprise Grade SLAs
  • 100+ In-Dial Numbers
  • Fax / EFTPOS Compatible

Business ISDN Options

Connect to either Optus Multiline or Telstra ISDN 10/20/30 and gain access to cheaper call rates. Monthly plans are available to new and existing ISDN customers and there are No Connection Fees when committing to a 24 Month Term.


You can transfer your existing ISDN service to BusinessCom and take advantage of our cheap call rates; or request a new service to be installed. Lead times for same carrier transfers vary between 10 and 20 business days. New installations have a lead time of between 30 and 60 business days.  

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.


Alternative to ISDN

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. Please call 1300 000 300 or CLICK HERE

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