While Integrated Services Digital Network (ISDN) is commonly used in businesses today -- it has become an old technology. First defined as far back as 1988, it became the standard for business communications.

It had the ability to handle the simultaneous transmission of voice, video, data, and other network services over the standard public telephone network. And was fast, reliable, and at the time the most fully-featured communications platform available.

ISDN was a popular technology for businesses as it allows users to attach multiple devices to a single connection line. In other words, rather than having to dedicate a line to each application of voice, video, and data -- a user could instead collect all of that technology into a single box and use that instead. Those older phone systems that many offices have, can do more than simply making calls in and, thanks to ISDN technology.

When first introduced, ISDN also offered speeds that were quite incomparable to anything else at the time. At 64, or even 128 Kbytes/s for both uploading and downloading, this speed was more than fast enough to run a businesses’ entire communications platform when it was new technology. It could also access packet switched networks, with the quality of the phone calls higher, than what was previously possible over standard phone lines.

Although nbn co -- the organisation responsible for the rollout of the NBN -- arranged to allow ISDN services to continue under certain circumstances. Telstra nonetheless advised existing customers on ISDN that it'll be able to continue using its services until between 2019 and 2022. Telstra will then roll out a series of cut-off dates. Once a final discontinuation of services date is determined, existing customers will no longer be able to make use of ISDN services.

Currently, Optus has not announced a similar discontinuation process for its ISDN services, but with the NBN affecting all of Australia's telecommunication infrastructure, Optus will be in a similar position to Telstra.

The process of making ISDN technology legacy is something that is being brought forward because the transition, from the technology can take anything from six to 18 months to complete.

As ISDN services become legacy, customers will have an opportunity to shift their service providers to organisations such as Macquarie Telecom. The service provider can offer a more tailored communications platform using newer technology. There is more choice and companies are encouraged to take the time, to make due diligence when selecting a replacement for their ISDN service. A business will need to develop a careful plan for change management, especially if it has critical systems like EFTPOS sitting on ISDN connections, and as such, the plan to make the transition needs to be articulated now.

All long-distance calls become 'local' calls, calls from within the organisation -- even to remote or branch offices -- become completely free. There's no longer a need to pay for separate voice and data lines into the business, cutting down on the cost per employee.

ISDN services were also expensive when scaling, as you would need to upscale in blocks -- hire one employee above the existing limit with ISDN, and you'll need to buy enough new access in multiples of 23. With SIP Trunking you add (and reduce) costs based on the number of employees there are, cutting down on the cost of expanding.

Where things get more challenging is in considering the security for the system. As with all technology-driven assets within the business, you’ll need to make sure the SIP Trunking system is adequately secure with firewalls, system and user account passwords. Although security measures -- such as firewalls -- might need special configuration in order to securely allow good communication without letting malicious attacks through.

It’s also important to engage with your telecommunications companies to develop a plan to port the phone numbers to the new system. In most cases it will be possible to do, but in rare circumstances it might not be, so you may need to develop a strategy to let clients know about the phone number change.

And yet, with the NBN, companies have a real opportunity to build a much more robust communications platform that will serve them into the long term, while adding extra functionality to help them run a more efficient and effective business. Many businesses that were still using ISDN were located in regional areas, where fast Internet speeds were limited. As the NBN rolls out to those regions, there will be no reason to maintain the ISDN connections any further.

Even if the NBN hasn’t rolled in your area, it's still a good idea to start preparing the business for the transition now, in order to ensure that the move to SIP Trunking is seamless, and can start returning value back to the business immediately.