ISDN is on Death Row – With No Reprieve

Paul Taylor at Voiceflex, a division of Frontier Systems argues that the days are numbered for ISDN.

ISDN was a major leap forward for the technology world in the mid 1990s offering voice communications such as Direct Dial In (DDI) and Calling Line Identity (CLI). At this point ADSL (Asynchronous Digital Subscriber Line) was very expensive and not widely available. Companies and individuals wanted a faster way to connect to the Internet, but the technology behind dial-up modems had reached its threshold. ISDN became a viable alternative to provide speeds of up to 128 kilobits per second (kbps), versus the standard connection of 30-53 kbps with a dial-up modem. The service was, and still is more expensive than analogue, users pay per DDI number and you pay extra for having CLI but the features are worth the investment.

But with new up and coming VoIP technologies combined with an increased demand for making cheap telephone calls over the Internet, what now for the infamous ISDN line? Is this the end?

IDSN was hailed by telecoms giant BT, that it would never be a voice service it would only ever be a data service backup for kilostream. On the same token the launch of XDSL led to the suggestion that ISDN would only ever be a voice service as it is too slow to carry data. As with all new technologies IDSN had its fair share of teething problems in the early days particularly with early adopters. Many businesses were sceptical and would knock the reliability of ISDN that is, until they could offer it themselves. That said, when faced with a new technology that is 40 per cent cheaper than ISDN lines and can offer call rates at a fraction of the cost of a regular phone call, it stands to reason that businesses will soon begin to question the feasibility of ISDN.

The rise in new VoIP technologies such as SIP (Session Initiation Protocol) Trunks as a competitive alternative to existing analogue and ISDN lines will provide businesses with a more cost effective and feature rich option for VoIP connectivity and as a result, will lead to the decline in ISDN users. Although much education is needed within the industry as to the real benefits to be had from advanced VoIP offerings, businesses will soon realise the advantages. The same learning curve occurred during the early days of ISDN and there is no reason why the same won’t happen again.

Weighing up the pros of new technologies over ISDN makes it hardly surprising that this dated technology stands little chance of survival. Using SIP Trunks, users no longer need one phone line per number as with ISDN, multiple numbers can be provided over one line or vice versa, resulting in increased cost savings and improved flexibility.

The next 12 months will be an interesting time for the VoIP industry and as market understanding of alternative ISDN technologies increases, businesses will begin to reap the benefits. We are constantly reminded that we live in a world where reducing cost is paramount for business survival and technologies such as SIP Trunks only serve to highlight the possibilities of saving money on a large scale.

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