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ISDN (Integrated Services Digital Network) are digital fixed lines unlike PSTN lines which are analogue.


ISDN2, or Onramp 2, is the most common ISDN service used by small and medium business.

ISDN lines are sold in groups of 2. They are not available to rent as single lines. For small business this means if you need three ISDN phone lines then you will actually need to rent 4 lines. You can end up paying for an extra line you don’t need.

Direct In Dial numbers for staff (100 number block)

Perhaps the bets feature of ISDN is the ability to have the optional 100 number block. Now this can be confusing but it’s worth it…

Rather than only having one advertised number like traditional PSTN lines, ISDN allows you to have numbers for each staff member if you like. For example, if you have 100 staff and 6 ISDN phone lines, then each can have their own private phone numbers.

However, it does not mean that you have 100 phone lines. We are talking about numbers, not lines. In this example only 6 phone calls can occur simultaneously because that’s the total number of lines. If a 7th caller rang in they would receive an engaged signal.

This is a fantastic feature for cut down the load on reception points and allow staff to have direct contact with clients. It is a completely optional feature and costs an extra $35 a month approximately.

Some companies also claim that ISDN call quality is superior to that on a normal PSTN line, but we think that unless you’re an audiophile (and listening really hard!) you won’t be able to tell the difference.

If you need more than 10 phone lines you should consider an Onramp 10 or primary rate connection. Read more..

Key Benefits with ISDN2:

  • Faster call dialling and connection/disconnection enabling your business to run to its maximum efficiency.
  • Greater bandwidth than your normal analogue phone line
  • You gain reliable, secure and clear transfer of data including graphics, studio quality videos and large data files. (You also gain internet and email access when purchased in conjunction with an ISDN compatible internet plan).
  • The service supports video conferencing, including live full colour, two-way video, audio and data communication
  • It complements existing ISDN phone systems and allows you to add more ISDN lines, as you need them
  • Infiniti will offer you comprehensive ISDN consultations, and where appropriate we will advise you on the best solution for your business needs.